My friends have also displayed this behavior. Being the inquisitive person that I am I asked them why they did that. Of course a lot of my male friends said that they liked to look at girls kissing because its their fantasy to be with two women and their 'disgust' at the two men is because they dont know how else to react. Most of my friends are sure of their sexuality but a few that aren't. The ones that aren't are the most vocal of their 'disgust'.

Oops...went a little long....hope this was a little helpful.

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Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. - Albert Einstein