Saying "some past conspiracy theories were true, therefore $CURRENT_THEORY is true as well" is both a non sequitur fallacy (you still need evidence for any new

Saying "some past conspiracy theories were true, therefore $CURRENT_THEORY is true as well" is both a non sequitur fallacy (you still need evidence for any new allegations) and survivor bias (you're not talking about the tons of historical conspiracy theories that were dead wrong). To expand on the non sequitur bit, here's an example I've used in the past: suppose I said, "The NSA has a constellation of mind-control satellites built with help from the lizard men!", and then responded to the deserved skepticism with "A lot of things that used to be tinfoil hat theories we now know to be true thanks to Snowden, so this is too!" Anyone can see that that's bogus reasoning, but that's what you're doing here. No matter what, every individual allegation needs to be backed up with its own evidence.