Perhaps you are just attractive. It's kind of the same way with people who are heterosexual. Why are some girls more attractive to heterosexual guys?
Why are guys attracted towards me? I'm also a guy.
Then there is something about you, the way you dress or look or something about you that is portraying you as a possible gay. It may be the way you walk but something is signaling these guys about you so best to do some self searching here or ask them why they think you're gay