Check out the ex-gay perspective on countering the poisonous message of gay-straight alliances. See PFOX's website. That's "Parents and Friends of Ex-Gays and Gays".
For example, see: "How to Respond to a Gay/Straight Alliance (GSA) Club at your school (a correct response to the anti-ex-gay group GLSEN): Ten Steps to Success by using ex-gay resources to fight bigotry."
And to hand out on the "Day of Silence", here's their downloadable pamphlet for teens: Feelings Change: They are Only One Part of You..."