Voting does work, it's just voters need to be vigilant. People have got complacent over the years in thinking the voting system is perfect, and this has allowed bad actors to usurp the system - particularly with new technology.
If anything, we should be voting on more things. Fire the politicians, replace them with lawyers who know how to write law, let the people vote on laws directly. We wouldn't have the bullshit over abortion if people voted on that specifically, rather than their favourite con man.
But if you supply them under the knowledge they will "defend themselves", that doesn't put you in trouble.
Not saying I agree with Israel or the US providing them weapons, but there's a bit of (perhaps bullshit) plausible deniability involved, and also the US is Israel's ally so they're supposed to support them in some manner (although I would say this should stop at providing naval support and generally protecting trade through the region, rather than providing weapons that are obviously being used for genocide).
It must also be remembered that these are not donations, even though politicians seem to frame them that way. Weapons and support is provided under bilateral aid agreements - it is a two way deal, and one that almost always favours the country that's giving. Israel is effectively taking out long term loans with the US to buy weapons.