Why do biuals/s get bugged by heterouals?

ok, im 14 and i recently came out to everyone that I was , everything is fine, no one really bothers (not even the s) except for ONE kid, i sit next to him in two cles, and in those cles hes often asking me y my gay friend and bi friend broke up, if they kissed, if they had , and wen me and my gay friend are talkin about people who might be bi or gay this kid is always being nosy and asking who those ppl are, and once i asked him y he was in our business and he said dat he wasnt gay and i said u cud b bi and ur not tellin me den he stopped talkin and ignored me. my friend thinks he might be bi because he flirts with me (takes my things and pencils and i usually end up having to pry it from his hands and it seems like we r holding hands, and he occasionallly pokes me, and recently he put my pen on his groin and i reached instantly but didnt realize it was on his groin den wen i got it he laffed, i dnt really consider it flirting tho) so yeaup, cud he be bi, and if so Y DOES HE BUG ME?! o and wen he found out that i was bi he asked me across the room wen i went to sharpen my pencil,