I respectfully disagree.
Sorry in advance if I offend anyone.
A relationship with a woman is something I cannot wrap my brain around. Thinking about straight sex makes me gag. The one time in my teens that I tried to have sex with a girl I could not perform. I've known all my life that I was gay. Never had any doubts about it. There is no bisexual in me at all.
Now, to get back on topic.
Nobody has a social obligation to come out. My only obligation to society is to not be a sociopath. Other than that it's nobody's business who I choose to have sex with or what my orientation is. Even in an absolutely ideal world where there's no chance of negative repercussions I still don't think anyone has an obligation to announce their sexuality to the world.
Now here's the really important part of what I want to convey in this message...
I prefer to educate the world one person at a time. Over the decades people that I've come to know are well aware of my sexual orientation. They see me as a hard-working, honest, decent, moral person who just happens to prefer guys to girls. That, I think, makes more of an impression than announcing to the world that I'm gay. So what if it takes more time to convince the world there's nothing wrong with being gay? Simply announcing to everyone that you're gay isn't going to change anyone's opinion on the subject. No, they need to learn first-hand that being gay or bi or whatever is perfectly acceptable. So, in my opinion bisexuals do not have any obligation to come out en masse.