I think profanity words was divided from moral humanity words by great Kings and religious high priests
where they felt not fit for there kingdoms /temples that seem to be used in hurmful ways, throughout time
more words created by going around other words gave cursing/profanity new standards that was outlawed
which shift into a political arena where law makes felt words was not humanly fit into our society as good
but evil/bad and harmful ......
This a very good question, but with the many slaves taught to live under the Christianity of slave-masters
they took on there meanings and cast out words throughout history til this day where we are taught words
are bad/ harmful and shameful, but used to express self of relief or acts of release.
I have no true answer , but like billions of others has accept the tren of such words not fit to be spoken
to and toward another humankind.