This goes back to the other thread where the OP is upset by the term businessman. I'm one of the people on that thread who thinks women can policemen, etc. I was told I was wrong. A pet peeve of mine is people only looking at the first dictionary meaning for words. If you look men/man up in the dictionary you will see that many times the word man/men is not meant to be gender specific.
I think it's fine if people prefer to use the words "firefighter, police officer, etc", but I do not assume that every fireman or policeman is a male.