Dumbing Cruder Effect

Usually the result of the Dunning Kruger effect. When the less intelligent a person is the smarter they believe themselves to be.
When they are unable to dispute real facts and evidence because theirs is only opinion based. They dumb themselves down even further by resulting to crude insults and childish name calling.

Claimant: "This is not a conspiracy theory. I did my own research to fact check everything!"
Doubter: "Your facts and evidence are all invisible because they are only in your imagination. All of your research is just other peoples opinions who agree with you. You are probably only repeating the opinions you heard from someone else."
Claimant (gets emotional and resorts to the Dumbing Cruder effect before leaving): "Well I believe it and I'm sticking with it. You're just too stupid to understand. And besides, you're just a big doodoo head!"