Hm, I´d think men find it nice because they like to watch it... why it should be cool among the ladies, I do not know.

I´m only half bi, I only like the upper half of women...

But I basically believe everyone is basically bi, otherwise cultures like the ancient Greek could not have been established.

As for the male bi crowd: For some reason admitting to being bi brings worse prejudice/disapproval to men than it does to women, at least in our culture. So I don´t think every man who is bi will walk around and proclaim it.