If there really was systemic child abuse and ritual murder happening all around you, any reasonable person would try to stop it

You would think that, but a reasonable person would also notice that no one else is concerned about this. And the few people that are concerned seem a bit funny in the head.

You would also notice that the bad guys always appear to be (((them))) and ignore it as anti-Semitic nonsense.

The people who believe conspiracy theories are not relieved when you point out the holes in their theory. This is the difference between “belief” and “desire to believe”.

Let’s say you believe this weekend will be rainy, and you are upset about it. You had cool stuff planned! You check the weather on Friday and notice the weather has improved. You would be happy to have your negative belief disproven.

That’s not what happens when you disprove someone’s conspiracy theory. They “want to believe” it because that belief gives them something: friends, purpose, etc.