The problem is that when the batshit-crazy people are crazy, they're really batshit, and the official story is a more comfortable option for anyone. Most people do not utilize true, rational thought, so to them the world is a false dichotomy: either the government is telling the truth, or the first person to formulate a new, completely-unproven conspiracy is correct. It's really just herd-like behaviour. Many of those assholes on Usenet you're referencing were really just spewing mindless garbage with no evidence, just like the lovely pro-Government trolls that infest this site do now.