If I were the victim of genocide, I wouldn’t be a voter at all, because I’d be dead. However, that’s kind of irrelevant - are you the victim of genocide? I’m assuming not, if you’re voting in the US election. Even if you’re Palestinian, your people are the victim of genocide, but unless you’re in Palestine, you aren’t.
That said, if you are Palestinian, I feel for you, I honestly do, and it would explain your view somewhat.
I think we can both agree that there’s only two outcomes that’re possible in this election: Trump wins, or Harris wins. (If you don’t agree, I’d be happy to hear your third outcome.) If you truly believe there’s no difference between the two of them, you need to do some research on the topic, because there are a lot of differences, even if they don’t pertain to this issue specifically.
If, between the two of them, you hope Harris wins, a 3rd party vote is voting against your interests. If you hope Trump wins between the two of them, a 3rd party vote is still voting against your interests, because you’re effectively taking a vote away from your preferred candidate among the two who could possibly win.
Edit to respond to your edit:
The outcome is the Democrats stop committing Genocide or they don’t get votes. “But Trump” isn’t even an argument.
Unless you’re out there protesting, or writing letters, or making phone calls, or in some way letting them know that their policy is costing them your vote, it’s a useless gesture. Posting on Lemmy isn’t going to change any politician’s minds. It’s not even going to change anyone’s mind here, in all likelihood. If you actually want to make a difference, you need to make your voice heard by the people whose minds you’re actually trying to change.