1. "Civil Rights movement"
So I take it you did not like the movie "The Help." Still, I fairly certain something like this had to exist, pretty sure "The Rosa Parks Story" fits this pitch, though it's been a while since I've seen it. It is kind of ironic that because nowadays audiences would rather expect to see black and white people interacting together, that's its harder to tell a story about segregation that can be taken seriously.
2. "Young gay man"
That's not really a pitch to what the story about, so yah I'd turn you down for it. As for a romantic comedy with a gay relationship where gays don't fit the stereotypes, seen it done with women. However, with men all of the examples are usually plots around manly men being secretly gay and having to tell their wife, which while not part of your description falls under a stereotype too.
3. Hero of a "War-torn nation" with "no Americans are involved on either side"
A bad way to pitch the movie, but it's been done. "Enemy at the Gate" even manages to tell such a story during WWII, where one Russian guy turns the entire war around and defeats Nazi Germany. This list gets really long if I can include movies occur before America existed, and in fantasies and scifi universes. But setting this movie in modern day with a small nation no one heard about would be very hard to pitch.
4. "Directionless young man rebels" "meets many people who've faced actual hardships"
I think you could pitch this movie, I just hope the producers don't try to make it a reality-TV reaction to rebels force to run into people with actual hardships. Don't think a public nuisance has ever been sent to prison in a movie, maybe jail, but not prison.
5. "A brilliant scientist" "defies societal taboos" "and make the world a far better place."
The pitch should be, let's make a movie about the life story of Nobel Prize winning Norman Borlaug. That guy has saved millions and his work is still considered controversial.
6. "Campaign staffer" to candidate who has "committed various moral indiscretions"
I never saw it before from that perspective, probably because it's assumed to be more boring to make a staffer the main character. Not sure what his conflict gonna be, if he believes in his candidate that much he can just not believe signs of moral indiscretions or simply put the person or the ideals before the act. Staffer/Candidate seems like a less known relationship for audiences than versions of this movie that already exist.
7. "Asian"
Again, you haven't pitch to me the actual plot of the movie, and have basically said "a movie about an Asian with nothing Asian in it." You must believe that the usefulness of a pitch is its emptiness. Well, this has been done independently and outside of the USA lots, but let's be fair Hollywood would be a little less conforming to 2% of the population. Still, I like to say it's been done as Asian actors have taken non-Asian roles and acted more stereotypically White or Latino. But even those aren't screamingly good examples. I think they would take this idea for a pitch, but then have the starting role be before by a white person, who may be altered to look more Asian. Because Hollywood will still completely miss the point.
8. It's a Horrible Life
This could be done as a comedy, otherwise you're basically asking for an entire movie to lead in one direction for the sake of subverting the audiences expectations at the very end. Unexpected plot twists do not make for a good movie, though this ending wouldn't ruin an otherwise good movie either. So it's kind of a nothing idea, compared to what was done before? think you'll need to name some funny or devilish actor who has agree to play the main part for this pitch to work.
9. "A man of spiritually devout" "dead for several minutes" sees no afterlife
A pro atheism movie? The pitch could work, but only when speaking with someone with their own agenda. Someone almost dies and now lives life to thief fullest is otherwise a bland idea on its own.
10. The gods must not be crazy
I really like the idea of this movie, kind of shocked it's not been done before. Classic artifact/mcguffin chase, which subversions of not wanting to keep the artifact, but from the point of view of the primitive guy entering the big city rather than the other way around. Hollywood would have every reason in the world to go for this pitch, which is really my best argument for why they wouldn't.