You have a completely different perspective than I. Yes, the Democratic party is being an ass to voters; yes, I hate them for what they're (not) doing; but I can slightly affect the odds to be slightly better for Palestine, so I will.
You can send a message that you're not a pawn, but they don't care, or at least in 4 years it won't matter anymore. If you want the best for Palestine, analyze your options for what's best, of which giving up and stepping back is not a very good one.