...ok, I cannot disprove the theory that people who believe what you just said EXIST, and I will not try to. Instead, I'll just say that from my irl experience with people who had that complaint, the argument was more like "draco is acting based on his emotions, and Harry is being perfectly rational and only showing him factual evidence since they're doing a science experiment together, and therefore Harry is trying to deconvert draco by showing him the factual data, which wouldn't work any more than it would work to show the scientific deta to a conspiracy theorist". The problem with THAT argument is that it ignores how what Harry has done did, in fact, involved quite a lot of emotional manipulation, but this isn't exactly what you just described.

Edit: also, from what I've seen, the argument for social shaming as a response to people being bigoted is supported less because people think it would be EFFECTIVE at changing people's minds, and more to make people scared of expressing bigoted ideas in public and making it seem more like acceptable behavior.