When I was in Kansas, I lived in a small town of 500 people. One night, in walks a California city-dweller into one of our bars, yelling about how small town people and small town life sucks. A few people tried to reason with him, calm him down, tell him that such abrasiveness was not a good idea since he was facing around 100 vehemently pro-small town people. He wouldn't listen. He kept up the assault. His little First Amendment exercise eventually got him an entire 6-pack of beer bottles across the face. He lost an eye, his pride and his desire to be such an asshole.
Was it regrettable that violence had to happen simply because someone was speaking? Absolutely. However, the result was unsurprising. If he hated small towns so much, why be there in the first place? I admire the professor for his attempt to spark debate about intelligent design in Kansas (and contrary to popular belief, there is probably a 50/50 divide of support within the state), but attacking fundamentalism as opposed to debating its merits just wasn't smart. Free speech can always be exercised (as I have proven with my opposition to fundamentalism), but it must always be done cautiously when facing great odds.
Well, on one hand I agree with you that it isn't very smart to provoke a large group of people who can show tendency towards violence...
...but, on the other hand, I don't agree that that justifies in any way beating someone up for speech. Violence didn't "have to happen"; it happened because a bunch of people decided to
make it happen. If someone walks up to me and starts yelling about how liberals suck, I'm not going to beat the guy up. I'm not going to particularly like him, but I'm not going to get violent. I don't think anything can possibly justify violence in retaliation for simple words. The mere fact that it was likely to happen doesn't make it okay that it did happen. I personally think that the people who got violent are more to blame for the violence than the speaker, given that no violence would have happened without their conscious decision (although the speaker is obviously not blameless).
