Simple proposition.
I think the average person has become more stupid, rude, and overall worse because social media rewards whatever behavior increases engagement with the platform. Someone writing a thoughtful comment may get noticed and liked, but someone writing a stupid comment will also get noticed(but for the wrong reasons) people's reactions to that comment increases engagement which gives an incentive for the commenter to double down on their stupidity since they're receiving both validation in the form of likes and responses.
I think social media has become like a form of the matrix. People choose to live in an alternate reality where the earth is flat, people's beliefs before the existence of the scientific method and germ theory are to be taken more seriously, and various convicted criminals and pedophiles are to be trusted to lead a country over people with experience. They choose to live in a reality where most women look like models, and most men earn an absurd amount of money and are built like D1 athletes.
Then when they unplug and have to actually interact with people in the real world, there's a kind of dissonance and yearning for the fakeness.