Why do rom-com manga authors feel compelled to add man-hating, yuri-bait characters to their manga? You don't see yaoi/yuri manga authors try to add a straight woman/man who's primary role is to fawn over one half of the main couple while treating the other half like trash, all the while the author tries to pass off her/his interference as a "cute quirk with potential for heterosexual fanservice". If yaoi/yuri authors did use that kind of character, they would more than likely put that character in the role of an antagonist.
And if you're gonna add a lesbian in your manga, that's fine, just stop making them misandrists who want to steal the main girl away from the main guy. Lovely Complex had a transgender woman in it and despite her affections towards the main guy, she never hated the main girl, in fact they all became friends after her introduction arc.