What you're suggesting leads to an offense/defense asymmetry. Spouting a conspiracy theory usually takes very little effort from the poster, they're either intimately familiar with it already or they just copy-paste the talking points from somewhere else (or both). Expecting others to write a deep rebuttal every time takes a lot of time, it basically amounts to a DDOS attack.

I reserve the right to dismiss low-quality posts with a low-quality answer. And yes, that's a judgement call. There is no way around that.