I actually find this very plausible. It's well know that homosexuals go through a great many condoms due to the nature of their sexual experiences and the degree to which their communities are at risk for STIs. Since condom manufacture is environmentally unfriendly and the resulting waste is hard to dispose of, they doubtless have a considerable negative impact.
Furthermore, I think it's clear that the increased metereological activity associated with concentrations of homosexuals could change the climate, especially as lightning could start forest fires and the accompanying increased rainfall might raise sea levels.
