Oh come off it.

Some people are stupid. Someone has to be at the bottom of the bell curve of intelligence. You can say, "but they have a lovely nature" or, "they are very skilled with their hands" or "but they are so pretty" as often as you like, but it still won't skip over they fact that they are stupid. Dull witted. Lacking in understanding. Lacking in sense. Not clever. Slow.

Telling someone they are stupid may not be polite, or kind or socially acceptable, but what if it's the truth? Calling someone out of earshot stupid: is that acceptable?Should we say intellectually challenged, and mention a learning disability or two?

Stupidity is not the same thing as ignorance, nor has it anything to do with being poorly educated.