I voted BLM, but I think it's a false premise and too generalizing because neither BLM nor Palestine are homogeneous groups of people. Not all of Palestine is pro-Hamas and not all elements of BLM support violence or defunding the police.
Black Lives Matter actually has a good intention, and I guess a lot of the rioters from 2020 were actually just a bunch of losers with no purpose in life rather than serious activists who would like to see things getting better for everyone. They certainly didn't do the cause a favor at all.
I would say the Palestinian cause is inherently bad to given even the PLO has always wanted the destruction of Israel as well which makes the cause inherently evil.
On the other hand with BLM the inherent cause is more muddied as it had two different premises which was police reform and believing systemic racism is still a major problem. The latter though is what ended up dominating all discourse and leading to all the truly atrocious ideas being proposed. If it was just about police reform, and not the latter it may have had gotten support as even simply a position of making it easier to fire bad cops would be a popular position as whether or not you have a high opinion of police departments or a low opinion, nobody likes bad cops(or bad public employees in general).
So I would say the Pro Palestinian cause is worse as there is no possible way such a position could be good while with BLM it was possible if it stuck to being about police reform rather than being about systematic racism