They're not evil, they're just stupid and consistently make stupid decisions and refuse to change anything about their behavior.

At some point the distinction ceases to be a difference. If the result is the same, is there really any difference? If a dumb teenager goes drunk driving and kills a family of four, is it really that much different than a grown adult murdering a family on purpose? Sure, you could argue the intentions are different, that the teen wasn't trying to get anyone killed. However, the result in both cases are the perpetrators are a menace to society.

If the stupid people were all clustered in one location away from all the smart people, and the two groups weren't forced to interact with one another, it would be fine. However, the real world isn't like that, and the smart people constantly have to suffer the consequences of stupid people making stupid decisions. Personally, I consider that to be a form of torture.