Some users don’t want to support a project that’s being developed by people they don’t like.
It’s kind of how some people left Reddit because of Spez, even though the amount of money Lemmy devs make doesn’t remotely compare, and the risk of enshittification/powertripping is minimal due to the whole project being open source.
I personally don’t see it as a huge issue, but I can see why it would be for someone (and I’d definitely see it differently if I was actively supporting the platform through donations).
Sure, it’s not like there’s a !luigimangione@lemmy.world community or a fuckton of related posts in other ones with no action taken whatsoever.