As for how heated the debate between evolutionists and creationists tends to get, I think that is just because it is one of the main areas of science that actively threatens and contradicts religious dogma and because of what is at stake for both sides as a result of that.
What's at stake for the Church is their truth and therefor their entire authority which is based solely on that truth. Therefor they have a kneejerk reaction to prove evolution wrong simply because it is the only acceptable outcome to them. That is where Intelligent Design and all of the Christian based evolution debunking sites and books come in.
The problem with those is that they are for the most part
utterly insipid (something that considering what you've been reading lately and your reluctance to defend ID I think you agree with). The majority of that kind of material is written by people who clearly have very little knowledge of the subject at hand and who are simply interested in blindly convincing themselves and anyone else they can reach that evolution is wrong and go about that in the form of employing pseudo science to make their explanation more credible than simply saying "It's wrong because the bible says so." It is that distortion of science that I imagine scientists find extremely aggravating and that causes them to be more aggressive in asserting their side of the story and hammering on the fact that their side of the story is actually based on something and is not on par with the creationist side at all.
For science minded people, what's at stake is science itself in a way. They fear the objectivity of science is at risk once "alternative" completely unscientific theories like ID become acceptable to be taught in class rooms alongside real science. Which would be a very dangerous precedent. People like Richard Dawkins essentially fear a new Dark Age where superstition and irrational thought win out over science and logic, something that would be extremely harmful for mankind as a whole. And while that is a bit overly dramatic in my opinion, you can't deny that especially in a country like the US there is a prevailing public opinion that does point into that general direction (I believe recent polls show something like 60% of Americans outright rejecting evolution and being in favour of creationism being taught in school alongside it).