A bro hater is usually a female that your bro is dating. They bitch and complain about everything and interrupt with bro sessions.
Male bro haters simply hate on bros for their good looks, impressive drinking abilities, and skill of fucking multiple girls in the same night. They can be seen at local Star wars conventions or playing video games on a Saturday night.
David: "Yeah man, Garrett isn't coming out because he is being a pussy."
Sean: "Why not man?" "There is a party tonight."
David: "Because his girlfriend is being a bitch and told him not to." "She's a slutty whore."
Sean: "Bro, she is such a fucking BRO HATER."
Male Bro Hater:
David: "Dude, he's such a bro hater."
Sean: "I know man. I can't believe Luis blew up about me fucking his 14 year old sister."
David: "Whatever man. High-five. Very nice!"