It's wishful thinking at best to believe that Twitter replies can effectively refute arguments. They don't establish public dialog unless the OP retweets the responses. You can't call it a dialogue if, effectively, there's only one person talking. Even simple refutations fail on Twitter.

"We can't fact check one person because it'd be hard to do the same for a large number of people" is classic perfect-as-enemy-of-good. We get huge bang-for-buck by handling some obvious outliers and known bad actors, and that's worth doing.