It's no accident, I'm sure. They are better, as they're not helping the killers, but they're nowhere near as good as is necessary to stop them. Pretty much the perfect definition of the average democratic politician these days: you vote for them to stop the killing, but you know that - whether by choice or not - they won't do anything to prevent more deaths when the killers come back into power.
I'm happy we're electing people like Zohran Mamdani, but we're going to need a lot more of them before our leftmost viable party can be considered even a little left. We need politicians that make change, and when the system doesn't let them, they band together with the rest of the population to force it, instead of just complaining about how they wish they could make change but can't. The leaders need to be leading the charge, to battle if necessary.
Better in a vacuum, yes, but as /u/disguy_ovahea@lemmy.world pointed out, a huge amount of voters pay absolutely no attention, and just vote for whatever color they've always voted for. Hell, a bunch of people searched "Did Joe Biden drop out?" on election day, because they paid so little attention that they didn't even know about Harris. That's an extreme example, sure, but it's just not a realistic expectation to think people will really think hard about a 3rd party, especially when it won't get a proportionate amount of attention even if it got a huge amount of support, thanks to the billionaire-backed media.
If we don't get someone into one of the 2 established parties, we're crippling ourselves, likely to the point of immediate failure. It would be significantly more viable to change one of the parties by flooding it with new socialist politicians than it would be to build up a new platform based on socialism from the start.