The problem is, it’s more than just the upvote. I don’t ban people for a single upvote, even on something bigoted, because it could be a misclick. What I normally do is have a look at the profiles of people who upvote dogwhistle transphobia, stuff that many cis admins wouldn’t always recognise. And those upvotes point me at people’s profiles, and if their profile is full of dog whistles, then they get pre-emptively instance banned.