If your guy, boyfriend, husband wants to wear something pretty underneath his trousers, there is nothing at all in wearing a piece of fabric that makes him gay, strange or whatever word you choose. It sure as hell doesn't make him gay. As a woman, if you're wearing tight pants and showing off your breasts, can I call you a whore/slut/tramp? And with that all of the negative connotations that go along with it? No, you wouldn't care for that would you?
So why are so many women so quick to judge a man that prefers to be a little different, wear something pretty or lacy, colors and cuts that you don't find in mens underwear? A guy wearing women's clothes signifies nothing about his sexual preferences. It doesn't make him a creep, weird or anything else, it just doesn't fit your stereotype.
Whether it's attractive on a guy is a matter of personal taste, just like so many women I see forcing themselves into too tight of pants, so many women that wear tight fitting tops with their stomach hanging over, in the end I think if they are comfortable with it then good for them!
And I don't see this is as crossdressing at all. If I'm out shopping and I find one pair of jeans that I like more because of the fit, look, whatever and they happen to be women's, then I'm buying them because I simply don't care what society or the manufacturer has put on the label or who their intended audience is. I am my own person and can make my own choices about everything in my life.
You can call it whatever you want. I feel sorry for all of the closed minded people out there, because if a guy wearing panties on you bothers you so much, I can only think of how you live your life judging everything by what society at large says is okay or not.