Spell checkers are politically incorrect

Apparently, spell checkers do not display suggestions for swear words.

So I was writing this email where I wanted to emphasize that I thought that the recipient was a motherfucker but in the hurry I misspelled the insult as mutherfucker.

I noticed that FireFox had underlined the word with the usual red squiggly line but so I went ahead and right-clicked the word and, to my surprise, the only suggestion was “rutherfordium”.
So I giggled at the suggestion and corrected the misspell myself by changing the “u” for an “o” and then noticed that after doing so, FireFox removed the red squiggly line indicating that the spell checker recognized the word as a valid/correct one.

I repeated the same steps with Chrome, IE and even Microsoft Word and they all behave the same: they do not provide the correct suggestion although each one varies on the provided suggestion(s).

How stupid is that?
After all, motherfucker is actually a word: http://www.merriam-webster.com/dictionary/motherfucker
So why hide it?

I just find these kind of things so stupid and ignorant… being politically correct is actually a bad thing!