"Ignorant" = "rude" a Scotticism?

[Douglas G. Wilson]

Here in Pittsburgh, "ignorant" is a word meaning
"rude"/"impolite"/"ill-mannered". No, I don't mean in some borderline
sense, like "ignorant of civilized norms" [although I suppose something
like this was an ancestral/etymological sense] or "rude because of not
knowing any better", I mean pretty much exactly synonymous with "rude" (as
opposed to the usual "ignorant" = "not knowledgeable").

This is not ethnically restricted as far as I can tell, and it does not go
along with a condensed pronunciation like "iggernt" (which association is
suggested in DARE). It is used in careful speech by educated persons
without self-consciousness; it seems to be taken as a "normal, correct" word.

I don't find this sense of "ignorant" in the conventional English
dictionaries. I do find it in the Scots dictionaries.

Perhaps this is another word which is shared by Scotland and Pittsburgh ...
like "slippy" = "slippery" or "redd [up]" = "tidy [up]" or "rift" = "belch".

Is "ignorant" = "rude" widespread in the US? If so, maybe it should be in
the standard dictionaries.

I note that in some contexts it may be difficult to tell whether or not the
word has its conventional meaning of "lacking knowledge". For example in
"These ignorant people are always using bad language" one can't tell
exactly what "ignorant" is supposed to mean. But in Pittsburgh (unlike many
other places AFAIK) one might say (without irony or oxymoron) "He knows
just about everything, but I don't like to talk with him because he's so
ignorant."

Please excuse any undue ignorance on my part.

-- Doug Wilson