The old George Carlin quote applies. Think of how dumb the average person is, and then think about how half of the people are dumber than that.

Besides that one of the roles of a politician is they need to be able to clearly explain an issue to the public. Most people won't be able to do this.

Besides our system requires that ever MP win the majority of the votes in a community. If a community is choosing a sociopath to represent them, there isn't going to be any better way to prevent crazies from getting power. Mostly the problem is people thinking posting complaints on the internet will solve issues rather than getting involved at the community level.

Our system is designed around people working at the community level, if people were willing to put more effort into their community they would have more influence over politics. But the internet makes people feel like they shouldn't do that so they complain on the internet instead and then complain about their internet complaints aren't accomplishing anything.