Usually but not universally. Some of them likely have acceptable IQs - the problem is that they don’t have the common sense that God gave houseflies. They’re misfits and contrarians, unable to prosper in decent society.
Whatever they are, whatever their “values”, if they are violent they need to be incapacitated - or dead.
Many years ago, I worked with some liberals. Some of them were pretty smart but didn’t have the discernment of an 8-year-old.
Most of these still look mentally-challenged to me.
Oh, they might have their Marx and Lenin and Obama memorized......