Why must we use gender-neutral terms when referring to police officers, but we assume that prisoners are male?

Well that really just gets right to the crux of it. Whenever something is positive, the appropriate thing is to be politically correct and gender neutral. This is now enforced in many settings, especially the academic setting. We (I'm in college) are now strongly advised to say his/her and such when writing papers or giving speeches. It's frowned upon not to.

Police officer. Mail carrier. Firefighter but not fireman.

Gunman, however, is totally acceptable! (Shouldn't they argue it should be gun-carrier? Or gunperson?)

I already know what the response to this will be: "Well, most gunmen are men!"

That's true. And most firefighters are men too.

Bottom line: if it's positive, you better make sure women are included. If it's negative? Suddenly it's alright if women are overlooked.

Do you really need to spend a lot of time discussing prisoners? If you do, and you feel strongly about it, I'm sure you can adjust your pronouns accordingly.

If you're such a delicate blossom that you feel you can't organise your language without being "corrected" first then maybe you shouldn't work in the prison system.

You might want to attempt to include the supposed gender specific terms you are referring to, as prisoner, inmate, etc can be male or female. Frankly I cannot think of a term that would mean strictly male or female when discussing prisoners. The pronoun attached, he/she, his/her would be determined on the actual sex of the prisoner.

prisoner, inmate, and so on are all neuter terms that refer to any gender. policeman and policewoman are gender specific. Use police officer. What prisoner term could be gender specific? Shower B**ch? Nope, still refers to both men and women.

I'm not very gender neutral. I'll say fireman, mailman, stewardess, maid, midwife, policewoman instead of like: firefighter, post deliverer, flight attendant, cleaner, police officer etc.

I know others find it offensive but I really don't (nor care very much)

I've honestly never heard people actually say "his or her" in reference to police, or anyone really. It's usually "his", or "her" if they're talking about a specific female officer. But yeah, if I had actually noticed that to be true it would bother me too.

The orientation is changing and soon you will get gender specific terms. Presently they are neutral in their connotation.

My opinion is that all of this 'political correctness' is crap! Call 'em whatever you want. Dare to be yourself rather than a sheep.

All because a special purpose or goal is to be obtained.

YOu do not have to. I hope you do not have to in your country.