I, like many of you, could defend both sides of this argument.
On the one hand, if you have never been exposed to gay culture before or even the idea of being gay or anything other than heterosexual, then seeing some form of that on TV or in a movie could be your introduction to a lifestyle or even just a way of thinking that you never thought possible or even knew existed. It could pique your curiosity and you could start looking for it in other, more positive forms. I understand where Harvey is coming from with this comment. A lot of the people interviewed in that movie made comments along the lines of, "I was just dying to see some sort of reflection of myself in the movies. Any little bit that I could identify with. I was craving it and would dissect every movie to see if I could find a gay character, even just a minor one." If you are in that kind of position, then yes, any form of representation would be desired even if it was negative.
And now the counter point. It's incredibly hurtful to the GLBT culture to have negative and stereotyped representations of people in movies that receive high visibility from a large portion of the country's population. Say you are that kid (or even, adult) sitting in the movie theater and you see a poor representation of a gay man. As we saw in "Celluloid Closet", gays were often used as humorous and were never serious characters. If they were, it was because they were afflicted with their sexual orientation. It was a problem, not a lifestyle. So, you're this kid sitting in the theater and your first introduction to anything GLBT is humorous, mocking, or negative. Instead of piquing your interest, that could totally set you off in the wrong direction. It could make you start viewing anything "other" as bad and something to be avoided.
Not to mention, depicting stereotypes on TV and in movies only reinforces them and justifies them in reality. Seeing it on TV only serves to validate the negative views held by society.