It starts with “huh those are some interesting ideas” and before you know it you’ll be screaming about vaccines and praying for Trump to make a comeback.
Oh, please, stop. Telling people not to expose themselves to certain bits of information or perspectives is just another form of bigotry. I read two of Ayn Rand’s books, because her ideas were new and fascinating to me. That didn’t turn me into a libertarian or stop me from seeing the flaws in her ideology. But I am now more educated and less likely to be influenced by libertarian arguments as a result.
Try having discussions with people who you feel have the wrong ideas about things rather than telling them to avoid “wrongthinkers” altogether.