I'm mildly put off by the people who want to include 'many other teens' in this message. Yes, it's true that lots of kids get harassed and bullied, not just gay kids. But the problems faced by gay kids is far worse. GLBT teens are 4 times more likely to kill themselves than straight teens. Hard fact. And in a lot of places, it is perfectly acceptable to harass gay kids, even while administrators discourage bullying of other kids. Gay kids often can't seek support at home from their own homophobic family. So I think it is important that this campaign is directed specifically to GLBT kids, and not just generally to kids that get bullied.
A Dish reader put it more succinctly:
The United Negro College Fund - what about Asians?
Of course lots of kids get bullied, but most fat kids, etc. have family who at least know their kid's situation, they see other fat people all over the place, and perhaps their parents are fat. I've never heard of a teenager having to say "Mom, Dad, I'm fat." And for gay teens who are afraid of telling their parents, sometimes the parent is part of the problem, maybe a father who's always yelling at his son to "stop acting like a sissy" or a religious mother who always drags them to a gay-hating sermon every week. For many gay teens it's less the bullying than the feeling that they're all alone, nobody understands, and nobody can help them.
I don't agree with your characterization of Megan's post as niggling. She effusively praises the project and thinks that even more young people could benefit from this type of effort. I saw no denigration in her comments.
Megan McArdle misses the point of the "It Gets Better" project. I'm one of the straight kids she talks about who was horribly bullied as a teenager (mostly in middle school). I was miserable for years and seriously contemplated suicide several times. But I got through it because I had something that many queer kids don't have: role models who had gone through the same things and come out of it okay.
People who lived through bullying as teens and went on to become happy adults are pretty common. But happy, out, queer adults who went through the same things are in much shorter supply, especially in rural areas. And queer teens are constantly being told that they are different from everyone else - unnatural or sinful or doomed to live a miserable life because of a basic fact of their identity - so they can't assume that what worked for straight kids will work for them. Many queer teens won't (knowingly) meet a happy gay adult until they graduate, leave home, and go someplace with a sizable gay population. Until then, Dan Savage's project will help.