That's just it, right there. If he had come out, while expressing these views, and said "In my OPINION, there are no such things as mental disorders", well then, I may still have a bit of respect for him. Acknowledging that your views are indeed opinion and not fact, and others are welcome to their own views as long as they respect yours as well....that's okay. What Tom did, on the other hand, was not cool. He came across as an ignorant, egotistical asshole by proclaiming explicit knowledge of something he's obviously fairly clueless about, and tried to pass his opinions of as legitimate fact. I lost total respect for him there, as I'm sure many of his other fans (or now former fans) did as well. Like that one guy on MTV recently said...
"I'm Tom Cruise! I'm the top drawing actor in Hollywood today! I wonder what can I do to F*CK that up?"