system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is there still controversy over vaccines?

The idea that "vaccines cause autism" was created by a fraud, and now dis-barred doctor. There are no studies supporting it. How is this still a thing?
gpt
Because of confirmation bias. The internet is large enough, and people are good enough at self-selecting information that confirms their own bias, that it's relatively simple to just remain in a self-affirming corner (read: circlejerk and/or hugbox) where everyone who disagrees with you is an idiot.