I think everyone has a story like this, about some word, Or phrase, or action they went about innocently, unbeknownst to them that what they were saying would be considered offensive.
Anyone who says they haven’t, I have to seriously question their honesty.
And like you said, most people, upon discovering what they’ve done, make a concerted effort to eliminate the behavior.
Then there are those who genuinely don’t GAF.
And I feel sorry for them.
How horrible to be unable to exhibit remorse or compassion or change.