It's only "voting bad" if you only care about this one, single issue. Compared to Biden or Trump, Harris's platform includes a lot of things I really want, so I'm going to vote for her - not because I have to, but because I want to. Yes, I'd greatly prefer her stance on Gaza was different, but this is not a Biden situation where I'm voting for him because there's no other option. If you refuse to vote for someone because you don't like literally 100% of their platform, you'll never cast another vote in your life. I'm honestly kind of tired of this "If you vote democrat, you're supporting genocide!" stance; it's tired, reductionist, and not helpful to anyone. Even if you convince enough people to vote third party that Trump wins, does that help Gaza? No, it makes the situation worse.
This whole discourse reminds me of some pro-Bush Jr. Family members who were complaining during those elections that the fiscal plan they liked (which caused the crash in 2008, but whatever) had been tied to trying to appease the single issue voters who cared about limiting abortion and LGBTQIA+ rights. This all or noting stance about Gaza feels just as singularly focused as those wingnuts.
Even if you convince enough people to vote third party that Trump wins, does that help Gaza? No, it makes the situation worse.
In the short term, yes, but when the next Gaza occurs—and if history is any guide, there will probably be another Gaza—the Democrats will think twice.
Besides, in 2020 if 1 million Californians who voted for Biden instead voted for Trump, the 55 EVs would still go to Biden. Presumably if any self-identified "political progressive" in California votes for Harris, wt:thon will probably be voting out of ignorance. Ditto, say, one in a very red state.