conspiracy theories and conspiracy theorists existed long before social media did.
This phenomenon isn't fundamentally new. Media has understood "if it bleeds it leads" for hundreds of years. What I think is new is how tight the optimization loop is, how personalized it is, and the way crowdsourcing the inputs leads to a firehose of content that isn't even attempting to be accurate or sane. It's a machine that automatically curates randomly sourced content for maximum inflammatory response and maximum addictiveness.
Here's another pile of examples unrelated to conspiracy theories:
https://www.reddit.com/r/ElsaGate/
This is what you get when you run the recommendation algorithm on random crowdsourced kids' content.