For some people it's just a matter of habit.
I know first hand from working with my father and other contractors that it's a part of the regular vocabulary - working with any contractor for a day is like going to cussing class for a term or two, depending on how long they've been working. I use it quite a bit and find that more often than not it helps to convey a message quite well - sometimes with passion, depending on how well you can use it. Yes it is a word, and some people don't like it - but you have to consider the day and age in which we live. People still expect chivalry and well-mannered behaviour even though most of that fancy stuff died out long ago.
In the end it's all opinion, and to each their own.. but you do have to realise that things change and it's only human instinct to evolve with the times, even if it's not in your agenda. Many people (myself included) who use the f bomb consistently in everyday vocabulary are also highly educated, qualified, and well brought up. When the time comes to act that way it is completely possible, but social standards and meanings are different from one group to another.
tl;dr - I drop f bombs a lot, but I'm also not a hillbilly - I can socialise like the royal family if need be. Some people just use it to express themselves, and if that's too much for you to handle, ignore them.