I swear some people I got a bit mad at the "-1" too there's tons of nude women on here but once someone puts on a nude guy oh my god call the president theres an emergency someone put a naked GUY on danbooru!
I think it's not simply that it's a naked dude. It's a naked dude in a demure, passive, stereotypically "feminine" pose. Makes dudes uncomfortable. Although really, anyone who's an anime fan should really be used to this sort of thing.