Yes there are stupid people out there but it is not the majority, even in poor areas as you are claiming. Let’s say you are even correct that poor people now are too stupid to understand anti vaccination groups are not science based. The solution is not censorship of anti vaccination groups, it is education campaigns to counter this. Education in schools, commercials, websites and social media. Not censorship of bad information.

That would require that people are actively interested in being educated. And to be honest most people aren't even in school, much less when they're grown up.

To make it worse, antivaxxers explicitly mistrust science and only trust the blogs and "mama groups" and other crap. How is anything the government, scientists, the media, anyone supposed to overcome that mistrust?