David Klinghoffer offers an interesting and plausible explanation, but I think it's only part of the answer. Here's a portion of what he writes:
You may have wondered why Darwinists in academia get so worked up about intelligent design. Reading what they write about our scientists and their work, you picture these guys turning red and sweating a lot. Alternatively, they try to mask their rage by getting all sarcastic and pseudo-witty -- a man of mature age like Larry Moran, for example, calling other adults "IDiots."The other part of the explanation, I think, is that these challenges and questions have only somewhat to do with science and mostly to do with religion. Most of the acidulous, angry Darwinians are metaphysical naturalists, they believe that nature is all there is. Naturalism is, for all intents and purposes, their religion and Darwinism is a critical support pillar in that religion. Students with the temerity to doubt Darwinism call into question the naturalist's deepest beliefs, but not only that.
Clearly, it's irrational because anger is almost always irrational. (I should know.) But even irrational fury typically has a trigger, and you might reasonably doubt whether the publications of scientists associated with the Discovery Institute are really, in a direct sense, that trigger.
[These people]aren't driven to their fury directly by the scholarly work of Michael Behe, Doug Axe or Stephen Meyer, but rather indirectly every time a student brings it up in class. Every year a new cohort of young people comes through the lecture hall and some number of them -- probably a growing number -- have been exposed somewhere to ID's critique and alternative to neo-Darwinism. Every time a student puts her hand up and politely asks something along the lines of, "But what about irreducible complexity?" it throws the class discussion down a totally different corridor of the mind than the professor meant it to go.
The professor can either dismiss the student with a hand wave and a casual invocation of "creationism," which makes everyone else wonder what this is all about, or he can explain the issue and try to refute Behe or Meyer, but that just raises more questions in the minds of some students who are inclined to doubt his authority.
Either way, how annoying for him! That's not on the syllabus! It's not supposed to be the program at all. It really puts our professor into an uncomfortable position. This explains P.Z. Myers's undisguised outrage when questioned in a non-academic setting -- a pub in Glasgow -- by a young person fresh out of college and on his way to grad school. The young man, our Jonathan M., was a stand-in for other students that professors encounter in their own classrooms and whom they, in that setting, are generally disallowed from abusing the way Myers abused Jonathan.
The thing is, these challenges from students are something that keeps happening year after year and class after class. It's a persistent irritant to our [professional academics], with personal and professional consequences for them. It's like having an ache in your neck or back that keeps coming back and you can never seem to rid yourself of it no matter what you do. Physical discomfort like that drives people to irritability that can seem both irrational and inexplicable, until you understand what actually drives it.
The intelligent-design movement is reaching these students and thereby their teachers, throwing the latter into chronic peevishness that we, in turn, see manifested in their public comments.
They also call into question the intelligence, competence, credibility, and authority of professors who have invested their lives in preaching the Darwinian gospel. These people have egos, and to be questioned by a mere novice in front of a class full of postulants preparing for initiation into the sacred rites of Darwinian orthodoxy is humiliating and insufferable. The querulousness they display is directly proportional to the affront to their egos and professional reputations.
Unable to make a convincing case, at least a case that's convincing to someone who's not already a believer, they lash out in anger against anyone who puts them in that embarrassing position. It's not the man who's confident in his convictions and able to defend them compellingly who resorts to rudeness and insults. It's the man whose noetic structure is fraught with insecurity and a sense of his own inadequacy in making a case for ossified dogmas that never before had to be defended who gets "peevish" when confronted with the need to do so.
