I was banned from a wrestling subreddit because I corrected someone who didn't understand how marginal tax brackets work. Not ad hominem and IMO I wasn't hateful about it, although I might've said something about how it's frustrating that some people spread FUD about how you're better off making $90,000 than $90,001 because that'll push you into the next tax bracket (there are a few edge cases where that'll hurt you financially, but there's pretty rare and the post I was replying to was solely about income tax IIRC)