I think we need to take a look at how we deal with the same issue in face to face interactions. Calling out someone who is incorrect in a group setting often go

I think we need to take a look at how we deal with the same issue in face to face interactions. Calling out someone who is incorrect in a group setting often goes poorly - you seem obnoxious and they need to double down on their rhetoric to save face. Even doing so "politely" just makes you seem more like a dick. While that may sound irrational, think about how you'd react at a conference where one person in the audience shouted "that's not true! this arcane reference which no one in the audience has evaluated claims that's just a myth!" in general you'd think they were at best misguided if not trying to be deliberately provocative. What are the odds that you would go home that night and look up the reference the heckler cited? Far more effective is to take someone aside and tell them in private that they are incorrect, especially when combined with acknowledgement of what they got right. In that context you are not attacking their social position and thus the stakes are lower. While it is hard to simulate such a position of privacy and trust in an online setting, private direct messages on most platforms are a good start. Anecdotally, people seem much more receptive to a respectful direct message and conversation seems much more cordial and focused on pursuit of knowledge. While I have no evidence that this leads to long term positive changes in posting behavior, I'd be willing to wager it has a better long term outcome.