Yes. In fact, it is a sign of male insecurity for a guy to tear down other men in order to establish his masculinity. A real man is able to love those who struggle with homosexuality. I went to an all-guys high school as well, and I took part in mocking guys who were effeminate. Our jokes, mannerisms, and voice impersonations were a constant announcement to the world that none of us understood manhood yet. Lurking under the mockery, though, was the knowledge that we would be scared to death if any of us had to carry the cross of same-sex attraction.
In the future, refuse to take part in such behavior. Better yet, stop the conversation or at the very least change the subject. Whatever we have done to another, we have done to Christ himself (Matt. 25:31–46).