I don't agree with you that it's only in North America where profanities are so widespread.
From what I know of the U.S through American T.V shows, music, movies
etc. it seems profanities are used in a more routine manner in the U.S than in other countries.
These words are a part of the language like any other. They can be most effective when used
Although they are useful when used to indicate emphasis, these words reflect on the (lack of) refinity of their user.