Since the demon fighter was introduced in 1985 his sexuality is not a crucial aspect of the character (nearly all of the character’s relationships in the comics have been with women).
Only few authors envisioned Constantine Bi. It will not affect 90% of the stories. Maybe we should be pissed about him not smoking, because Bad Habits won’t be done originally but even that is not a problem.
Point is most of the people here are not even fans of character, they just want to be in your face about gay/bi rights being trashed, but that is not a case here.
Do us a favor, ignore this show, and boycott it by not watching. Don’t whine and bitch about it, trying to get NBC to take it down. You will fail!