Palestinians are quite liberal and progressive compared to other Arabs, and being gay is legal in the West Bank -- that doesn't mean that there's no issues, this article about a planned LGBT youth camp gives a good impression. There's allies, but keep your head down and out of sight of religious nutjobs. It's pretty much the same thing atheists do over there: Plenty of them around with all that secular history but the religious nutjobs are simply too rabid to allow public discourse about the topic. It's way easier to go the "secular Muslim" route: Fast, but not for Allah.

In Gaza the legal situation is undetermined (scholars disagree on whether British mandate law prohibiting gay sex still applies) but anyway Hamas is in power, they instituted a religious police, tried to enforce headscarfs, go after male hairdressers cutting women's hairs without any legal basis etc. don't look at the statute book Hamas doesn't care and they're crazy. Also you don't want to go to Gaza right now. Also, you probably can't even if you're an UN aid worker.