Are you really that shocked there are people who believe in a flat earth, considering all of the other ludicrous things people believe? We're humans, we're fallible, our brains look for patterns and connections that may not actually exist. We've always been this way and we always will be.
Why would he, or anyone for that matter, be forbidden to launch a rocket (assuming all of the legal aspects had been taken care of)? I'm not sure if you're asking seriously but who would be the arbiter for allowing or forbidding freedom of thinking? Seems to be a slippery slope to me...
It appears this man was very much a proponent of questioning the world around you; what's wrong with that? Did he take it too far? Probably. "It pays to keep an open mind, but not so open your brains fall out.” (Carl Sagan)
I'm just disappointed he wasn't able to successfully launch the rocket and see for himself that the earth is, indeed, spherical.