I read a more in-depth analysis some time ago and a lot of them are just desperate people with financial or other problems, and becoming a Reichsbürger is more like a form of escapism from reality than something they really believe in. Imagine you have a crippling amount of debt and/or are about to be evicted for example, and then you read on some nutjob website that the state actually doesn’t exist so you don’t owe them anything and they have no authority to evict you, doesn’t that sound great? All your problems solved by just burning your German ID card and printing out a new one of some made-up country. Of course reality gets them eventually but psychologically it’s easier to bear for some people to believe that they’re the victim of a huge conspiracy rather than face the fact that they fucked up and are screwed.