But Legends of Tomorrow has a lesbian female lead in Sara Lance, and I don't hear any outcry over that. (We've already heard that Sara's going to be attracted to Supergirl in the big crossover next month.) Not to mention gay supporting characters like Curtis on Arrow and Captain Singh on The Flash. And plenty of other CW shows have had lesbian or bisexual female characters, including The 100, The Vampire Diaries, Jane the Virgin, and Supernatural, although several have been criticized for a tendency to kill off such characters.
So including lesbian/bi characters on yet another CW show would hardly require courage; if anything, it's practically routine by this point, and it's not something the CW's target audience would be likely to have a problem with.
Indeed, next week's Supergirl episode will feature the debut of Maggie Sawyer (Floriana Lima), who's one of DC's most prominent lesbian characters. It's not yet established whether her sexuality will be addressed in the show, but given prior precedent, I expect it'll be acknowledged as casually as it was with characters like Curtis and Singh.