Conspiracy theories involve people accepting a hypothesis before they have reasonable justification, often because of bias or misinformation or some other prior conviction. These hypothesis usually aren't mainstream, and involve some sort of special, hidden knowledge but not always.

That doesn't mean they are wrong, it means we have no reason to accept those ideas as true. We are using poor critical thinking by accepting these bad hypothesis we call conspiracy theories. The door for good evidence is always open, the problem is these people usually don't even understand what that is or have any basic ability in science and math.

Its important not to dismiss unorthodox hypothesis, but its irrational to not apportion belief to the evidence. The problem is most conspiracy theorists are people who usually aren't even capable of understanding scientific evidence.

From a pragmatic sense you should mostly ignore those people. Putting the .010 batter in ur lineup just because you think his swing is unorthodox is still dumb. Yes they might get a hit, but we only have finite time and resources and until they learn how to swing a bat properly its not worth the time.

Maybe we miss out on that one rare hit, but we skip 100 bad outs and get a lot more hits in the long run.