Who says I’m doing nothing about it? All you know about it is that I refuse to vote in favor of genocidal regimes. Besides, refusing to vote for someone who’s actively committing a genocide is doing something. It’s exercising your right to vote in a meaningful way by showing that there are lines you do not cross. I wouldn’t vote for Hitler when that was an option, and I won’t vote for Harris (or Trump) now.
So they can feel like they’ve done their civic duty without actually effecting any meaningful change.