Captain America - That's heavy Cap.

Marvel doesn't hate LGBT. Sorry kiddies but profit runs the world not your feelings. Sure they could add a LGBT super hero but specific countries like China, Russia, etc.. might ban it, or even forbid Marvel from showing future projects. Maybe the problem isn't that Marvel doesn't want LGBT-representation, maybe the problem is ACTUAL homophobia and ACTUAL transphobia in these countries.

The real, underlying, problem is that Hollywood producers need to think about the international box office.

Sure, there is nothing wrong with having LGBT protagonists…but when you think as a worldwide investor things get a little complicated. You movie might get banned in China, The Middle East, half of Africa, and almost the entirety of South Asia. Thats ~35-40% of the world's population (China alone is ~16%) who will not pay a ticket to your film because it was banned there.

It's like NC-17 movies: No theater will carry them, so they don't make it. The same problem affects LGBT characters: A lot of countries will not carry them. So both options are, in a depressing way, box-office poison.

You can say Hollywood is racist/sexist/whatever…but at the core of it, they're business people. They're gonna do whatever they think will yield the higher profits. Having your movie banned in 40 or so countries because you dared be progressive is a sure way to drop those profits.