Straight people have never had the opportunity to "ruin" the gay community because, by rejecting us, they propitiated the creation of safe havens where we could express ourselves, unite and flourish. Threats from the outside world were what made the gay community a rich, peculiar and diverse place. However, as we reach the mainstream, we are bound to lose part of that identity created by exclusion, and we will be forced to make changes and adopt a different perspective on what being gay means, and where we stand as a group. To become more accepted, we have to pay the price of losing what we were... To be honest, I am not sure that becoming diluted into "normalcy" is as exciting and empowering as some might want to believe, but well, being mediocre and invisible is better than being persecuted, I guess.
As for the people who might be ruining the gay community from within, who are you referring to? Conservative gays? Bitchy, hedonistic, beauty-obsessed gays? The apathetic and indifferent younger generations? They are not ruining everything, in my opinion; they are just a reflection of the diversity within every group... There are arseholes everywhere, after all. 
