They start out as discussions, but it only takes one party to turn that into an argument. Generally though, continuing the argument is more to convince onlookers than the argumentative party.

It can be frustrating to go from a thriving niche subreddit to a new venue without anyone to populate those niche communities. Outside of ML, FOSS, and Star Trek, most of the niche communities are ghost towns.

I don’t think anyone is suggesting convincing AskReddit or /r/memes to migrate. I think they’re mostly targeting /r/ObscureInterestYou’veProbablyNeverHeardOf.