Nowadays in the English-speaking countries, everybody swears.
Swearing is so popular. You hear people swearing in movies, on TV, in dramas, in the news (may be not in natural history programmes)
Many people couldn't speak without being swearing at the same time. When I told a guy I was upset by the high frequency f-words in his speech, he apologised, but still kept swearing when he’s talking.
You might have learned some swearing words from watching US-made movies.