You shared this verse: "Therefore the Law has become our tutor to lead us to Christ, so that we may be justified by faith. But now that faith has come, we are no longer under a tutor. For you are all sons of God through faith in Christ Jesus" (Galatians 3:24-26). After the tutor teaches us, we do not forget or totally disregard the teachings and go our own way.
Jesus said in Matthew 5:17-18: "Do not think that I have come to abolish the Law or the Prophets: I have not come to abolish them but to fulfill them. For truly I tell you, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished." Not everything in the Bible has been fulfilled. Jesus hasn’t come back yet, and we have not gone through the end times.
Why would a loving God give us something so bad as the Law that Jesus had to take it away along with our sins?
You are correct that we are not to disregard the teachings found in the Old Law. "For whatever was written in earlier times was written for our instruction, so that through perseverance and the encouragement of the Scriptures we might have hope" (Romans 15:4). However, you seem to have missed Paul's point in Galatians 3:25. While we recall the teachings, the tutor no longer has authority over our lives. We are under a different law today. "He takes away the first in order to establish the second" (Hebrews 10:9).
The difficulty is that we cannot be under two covenants at the same time -- just as a man cannot be married to two different women or a woman cannot be married to two different men. "For the married woman is bound by law to her husband while he is living; but if her husband dies, she is released from the law concerning the husband. So then, if while her husband is living she is joined to another man, she shall be called an adulteress; but if her husband dies, she is free from the law, so that she is not an adulteress though she is joined to another man. Therefore, my brethren, you also were made to die to the Law through the body of Christ, so that you might be joined to another, to Him who was raised from the dead, in order that we might bear fruit for God" (Romans 7:2-4).
You object to the Old Law ending because everything in the Bible has not been fulfilled and quoted Matthew 5:17-18. Please note that you played games in your argument. Jesus' second coming is predicted in the New Law. The "end times" is a product of men's imaginations and are not found in the Bible (see Premillennialism). To use things not in the Old Law to claim the Old Law was not fulfilled is not an honest argument.
The word "fulfill" in Matthew 5:17 comes from the Greek word pleroo, which means "fill, make full, supply fully, complete." Its meaning can be seen in how it is used in other passages. For example, there are numerous passages that speak of something being done in order that a prophecy might be fulfilled, such as in Matthew 1:22, 2:15, 17, etc. The word means that the prophecy was answered in full and brought to completion. When something is made completely full by a task, the task is finished. We say this in English when we say we went to the gas station and filled up the car. In other words, we stopped pumping gas into the car once it reach the full mark because no more gas could be added. This sense of a completed purpose is seen in Luke 7:1, "Now when He concluded all His sayings in the hearing of the people, He entered Capernaum." The word "concluded" is the Greek word pleroo. Jesus fulfilled his purpose in that particular lesson. There was nothing more that needed to be said at that moment, so he stopped. It is also seen in Acts 19:21, "When these things were accomplished, Paul purposed in the Spirit, when he had passed through Macedonia and Achaia, to go to Jerusalem, saying, 'After I have been there, I must also see Rome.'" Paul had completed what he set out to do in Ephesus, so he looked to move on to another region. The same Greek word pleroo is being used, though it is translated as "accomplished."
By stating that the law would continue until all was fulfilled, or made complete, Jesus is implying that the law in its current state was not complete. We know from the apostle’s writings that the Mosaical Law was missing some essential parts. It was unable to give its followers life (Galatians 3:21). It could not make its followers perfect (Hebrews 7:18-19). Thus, it had a fault, not in itself, but in the inadequacy of those who tried to live by it (Hebrews 8:7). It could explain and hold a person accountable for sin, but in itself, it could not cleanse sin (Hebrews 10:1-4, 8-10, 14). It took the sacrifice of Jesus to bring into existence the missing elements (Hebrews 9:15).
The difference between destroying and fulfilling the law is the same difference between declaring a mortgage note null and void, tearing it up and throwing it into the fire, and paying the note off in full. Both bring the mortgage to an end, but it is done in vastly different ways. Jesus did not cancel the law but brought it to a natural conclusion.
Jesus explained what he meant by "fulfilled" when he emphasized that the Law would not end until all was fulfilled. “For assuredly, I say to you, till heaven and earth pass away, one jot or one tittle will by no means pass from the law till all is fulfilled” (Matthew 5:18). This "fulfilled" comes from a different Greek word, ginotai. It means, "to be, to come into being, to be made, be done, become, or to be celebrated." Jesus is stating that the permanence of the law was conditional. He gave two possible ending conditions: either heaven and earth would come to an end or all is accomplished. His phrasing is similar to the parent who tells his child, “You’ll set here all night until you eat your peas.” The implication is that the child would not be at the table all night; the peas would be eaten before then. In the same way, Jesus is saying that the world would have a better chance of ending before God accomplished His purpose for the Law. Some people focus so hard on the first condition that they miss the fact that the second condition would occur before the first. The same type of phrasing can be found in Matthew 24:34 and Luke 21:31-33.
Another verse that speaks to this same topic is Romans 10:4, "For Christ is the end of the law for righteousness to everyone who believes." The word translated "end" is from the Greek word telos, which means "end, termination, conclusion, aim, result, goal, outcome." In other words, the purpose of the Law culminated in Christ Jesus. Jesus was its goal. With His death, he brought the law to its conclusion. "Having wiped out the handwriting of requirements that was against us, which was contrary to us. And He has taken it out of the way, having nailed it to the cross" (Colossians 2:14). Or as we already noted, "Therefore the law was our tutor to bring us to Christ, that we might be justified by faith. But after faith has come, we are no longer under a tutor" (Galatians 3:24-25).
Your last question is not about what you believe. You don't believe the Old Law was bad and neither do I. "So then, the Law is holy, and the commandment is holy and righteous and good" (Romans 7:12). The Old Law served its purpose in showing men their weakness. "What shall we say then? Is the Law sin? May it never be! On the contrary, I would not have come to know sin except through the Law; for I would not have known about coveting if the Law had not said, "You shall not covet." But sin, taking opportunity through the commandment, produced in me coveting of every kind; for apart from the Law sin is dead. I was once alive apart from the Law; but when the commandment came, sin became alive and I died; and this commandment, which was to result in life, proved to result in death for me; for sin, taking an opportunity through the commandment, deceived me and through it killed me" (Romans 7:7-11). The problem is that covenants involve two parties and the Israelites were unable to keep the terms of the covenant. Thus, the question is the same that Peter asked, "Now therefore why do you put God to the test by placing upon the neck of the disciples a yoke which neither our fathers nor we have been able to bear? But we believe that we are saved through the grace of the Lord Jesus, in the same way as they also are" (Acts 15:10-11).