Why do you believe in God? If God loves us all, why doesn't He let us all in heaven?
Why do you believe there is a Sydney, Australia? Assuming you never been down under, what makes you believe that it exists?
There are multiple interlocking reasons why believing in God makes sense. I have a degree in science and I remain strongly interested in various aspects of science. One of the things that fascinate me is the complexity and orderly design of even the smallest system. I listed out just a very minor number of them in a lesson: "Remember to Magnify His Work." Would you take a moment or two and look at them? You see, if I found a watch laying on the ground, I won't immediately think, "Look! A watch just grew here!" The existence of complexity and design tells me that someone made it. For the same reason, I love looking at the complexity and design of life around us because it makes me marvel at the mind and power who made it.
For the same reason, I realize that the Bible isn't a creation of man because men have not been able to write a book like the Bible. People have tried, but they have always failed. The quantity of information in this short book is amazing. Think of what happens when people try to write laws -- we end up with enormous bookshelves of laws, often contradictory and constantly expanding because the prior laws were never quite what was meant. Yet the Bible is able to tell us what needs to be done, without contradiction in a book that I can carry around. It has been applicable for thousands of years and people spend their entire life studying it and always finding greater depth to it than the last time they looked at it. Here is another lesson to read through and ponder: "Why Believe in the Bible?"
I would like you to read two very short books by a man who used to be an atheist and was forced to change his mind. The books are "The Case for Christianity" and "Mere Christianity" by C.S. Lewis. It is easy to scoff; that is, it is easy to dismiss something without examination. But scoffing isn't reasoning, it is a sign of ignorance. I'll be impressed if you read and consider these things, and then tell me what are the alternative explanations for the arguments which demand that God doesn't exist.
In regards to why doesn't everyone go to heaven, you are basically stating that everything as it currently exists is perfect just the way it is. Nothing needs to change. You want the guy who sliced people's heads off on a bus to be treated just the same as the lady down the street who bakes cookies for the neighborhood children, just because she likes to do it. If such ought to be, then why do men lock up or put to death heinous murderers? Why aren't they allowed to roam free and do as they please?
What your view doesn't allow for is justice. It doesn't take into account that there are people who choose to be mean, violent, and wicked. "Truly, this only I have found: That God made man upright, but they have sought out many schemes" (Ecclesiastes 7:29). God made you, me, and everyone else in the world righteous and good. It is we, not God, who chose to leave that state of righteousness. God's preference is to save everyone. "The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance" (II Peter 3:9). But the sad fact is that most people don't care. And God's justice won't allow defiance to be ignored -- if He did, then He would not be just or righteous -- just as we call men unjust when they let a murderer go free. So is the problem on God's side or man's? You lay the blame at God's feet, but I don't think you are being fair.
I know I gave you several reading assignments already, but if you really want to tackle this issue, there are a lot of things you need to consider before you can say you are able to make a fair judgment of your own. I have one other lesson for you to read and do, it is called "The Judge of All the Earth." God is love, but God is also just. Love doesn't cancel out the need for justice.
Wow! That made a lot of sense and words can't describe how happy I am right now. I didn't think of it that way. I'm going to read the lessons tomorrow.