first thing is that we have very sensitive testicles, and having such little space to fit anything in just wouldn't be comfortable. besides thongs are made for a sexy body outline, guys couldn't have that if they tried... well maybe i'm biased being straight, but still guys don't have that sexy figure.
Plus I like that there is something covering my cheeks, and that I have less chance to get a wedgie, plus they just look completely uncomfortable.
I have always gravitated to the less is more view, so for me over time I found myself trying to find the most minimal types of underwear I could find. I also like quality made in the US stuff, so when I found this one company doing both, and even making really nice guys g-strings, I was in heaven. Their stuff is all guy specific, with a great roomy fit. Now I virtually never wear briefs or bikinis anymore. Perfect for under jeans when riding a motorcycle (NO bunching). :)
What a dumb question. How come girls want to wear thongs when guys aren't even the ones asking for them in the first place? Girls wear thongs because they think it's trendy. Not because men wants you to.