Well you're getting the wrong impression imo. Who says sexuality is minor? If for example Widowtracer actually happens and we have this relationship between Tracer and Widow where the former tries to redeem the latter yadda yadda yadda, then whether she likes dick or puss is pretty relevant. Or maybe it won't be and it will just be a piece of trivia as irrelevant as her favourite cereal. But useless trivia like that still adds flavour to the characters and is fun to know.