Quite apart from the changing nature what is considered taboo in the English-speaking world, fuck has undergone weakening though overuse, and has lost its potency. It is simply not as profane as it used to be.
This inflation of profanity is a linguistic commonplace: 150 years ago, the profanity to avoid in polite company was damned. In fact, it is a characteristic of vivid language in general; that’s why slang has such a short shelf life.