I get the argument for engaging with folks on $8chan (AKA "birdsite"), especially if it's in hopes of persuading them to leave it behind. I've done a fair bit of that myself before taking my account private.
But there is also the strength of the network effect. Don't think of it like a "one person, one vote" type of decision -- think of it like a protest or strike. Every account that's truly gone makes it an easier decision for the next person/org. Your individual choice really matters a lot.