It's called jelousy, and insecurity. Go ahead and tan bro,...keep yourself in shape, and looking good. Eventually when one of these clowns rips on you for tanning, tryin' to make you feel bad about doing it... (Why they would??? insane???) give em' a good fist sandwich to the mouth. Eventually with enough of these,...they will shut up. As for the chicks that do,....they are the ones you stay clear from. Believe me, these same whores will be sweatin' for your ass pretty soon if not secretively already. Say "fuck-em" for now...Do what you want, don't make anybody tell you what to do or like. C'mon,...be your own man. It's better like that.
Good Luck