Well, you're right that believing bullshit without a good reason can be a problem. A big problem. For example, anti-vaxers. But even there, individual anti-vaxers aren't much of a problem (except to themselves and maybe their kids). It's only when they start organizing and occupying power positions where they can change laws and endanger everyone else that they become an actual issue.

Then again, many people believe many things without evidence, but a lot of it doesn't really harm anyone else. Believing something in itself isn't necessarily an issue.

I could believe that an invisible purple elephant controls the people around me, and it wouldn't hurt anyone else. They'd laugh at me when I told them, but that's about the end of it. People can believe whatever bullshit they want for themselves. As long as it doesn't hurt anyone else, do/think/believe whatever the fuck you want. When you believe in some wizard on a cloud who controls and judges your life, that's your problem. But when you find millions of others who believe the same crap and then you organize and try to force your beliefs on others, that's the problem.

Belief =/= religion.