There is a preacher in El Paso, Texas, who wrote this article http://www.wordsoftruth.net/wordsoftruthbulletin08_10_2008.html. Please read it. Is this Christian like or not? I wrote him an email and told him that it was unchristian like. Insulting people in the way he did was not going to change anything. I asked him what Jesus would do. He said that God commands us to use offensive language when exposing someone. Now, just a minute!! No, God doesn't command us to do that. He speaks against that (I Peter 3:8-10). He told me that I twisted 1 Peter 3:8-10. No, I did not. Jesus did not expose people in the manner that this preacher does it. He told me that I was foolish and ignorant. He needs to understand that calling people foolish is sinful (Matthew 5:22). He claims that I owe him an apology and I need to repent of the message I wrote him. What should I do? I am very angry right now. I don't put up with people calling me ignorant and foolish. My parents don't either.
I'm not an apologist for other preachers, so I'm going to avoid the personalities, and just focus on the issues at hand.
First, you need to calm down. While you are angry you are not going to think clearly. I'm not being harsh, it is a simple matter of fact. "So then, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath; for the wrath of man does not produce the righteousness of God" (James 1:19-20).
The article sets up a straw-man. He makes it clear that there isn't a particular congregation or preacher in mind. He gives a sample "lesson," but it is clear that it is taken to the extreme in order to illustrate a point. No one is being insulted, so your initial charge was too harsh of a criticism.
You asked if Jesus would use harsh language to make his point, the answer is clearly "yes." Matthew 23 stands as a beacon to this approach. Should it be used constantly? No, it is not always called for but there are times when it is appropriate. Take, as an example, the situation between Paul and the sorcerer. When Elymas interfered with the teaching of the gospel, Paul told him, "O full of all deceit and all fraud, you son of the devil, you enemy of all righteousness, will you not cease perverting the straight ways of the Lord?" (Acts 13:10). God supported what Paul said because Elymas was struck blind as a result. Have you ever read the teachings of John the Baptist? See Luke 3:1-15. To some people, it is a wonder that crowds would come all the way out to the wilderness to hear such "no-nonsense" preaching. There is an article I would like you to read that might help clarify the point, see "Jesus: Intolerant, Confrontational, and Exclusionary."
"Finally, all of you be of one mind, having compassion for one another; love as brothers, be tenderhearted, be courteous; not returning evil for evil or reviling for reviling, but on the contrary blessing, knowing that you were called to this, that you may inherit a blessing. For "He who would love life and see good days, Let him refrain his tongue from evil, and his lips from speaking deceit. Let him turn away from evil and do good; let him seek peace and pursue it" (I Peter 3:8-11).
What Peter says is true, but it does not rule out calling evil for what it is, evil. To degrade a brother, to give false reports (deceit), and the like is wrong to do. But that wasn't what the article did. The author pointed out that there are preachers who are more focused on their position and making an income than in teaching the truth. Paul warned that these types of people would always be a problem. "Preach the word! Be ready in season and out of season. Convince, rebuke, exhort, with all longsuffering and teaching. For the time will come when they will not endure sound doctrine, but according to their own desires, because they have itching ears, they will heap up for themselves teachers; and they will turn their ears away from the truth, and be turned aside to fables" (II Timothy 4:2-4). Peter also warned, "By covetousness they will exploit you with deceptive words; for a long time their judgment has not been idle, and their destruction does not slumber" (II Peter 2:3).
About the only sad thing I read is the claim that most of the preachers this author met are of this sort. I would hope that it is not true, but then I don't move in the same circles that he does. I have met men who are more concerned about retaining their jobs than teaching the truth, but I know far more who are sincerely devoted to the preaching of the whole gospel and the saving of lost souls.
(By the way, did you notice that in objecting to this preacher's harshness that you became harsh yourself? It is something I noticed happens a lot. People will condemn another saying "You shouldn't judge!" Never realizing that they are doing the very thing they are condemning. It must be something in human nature.)