In most cases, you have no way of telling A and B apart unless you are directly involved or an expert.

Debunking has limited effectiveness even in factual situations, beyond factual, not even sure what that would mean.

There is, of course, also a numbers game, flipping the side of a few people is quite sufficient for a some things, so even being really good at countering adversarial propaganda will leave a lot of gaps. Reducing an attack surface might not always be a bad idea.