Well there are at least three conversations going on here.
1. Should a person use profanity/ does profanity have a special place in language/etc.? I've obviously got opinions there, but nothing that belongs in tactics. (Couple of really amusing stories there, but I digress...)
2. Is the use of profanity by someone confronting you an additional warning sign of bad intention/escalation toward violence? I expect that varies in a lot of different environments. When used between strangers in a place where that is not customary, yes, I take it (and took it) as an additional warning sign.
3. Is it tactically a good idea for a defender to use profanity? Now, that's interesting.
I have taken some courses on armed SD. I have been made to practice during those drills some "verbal compliance" or "command voice." All of us at the line shouting (as we drew our guns) "STOP!" or "DROP THE WEAPON!" And I have practiced the same myself at my club.
I was never drilled on "GET THE ____ BACK!" and I would be reluctant to practice that at my club. How great is a technique if you can't practice it?
Also, there is the legal concept of "incitement" or "
fighting words." You plan to say (or do say) "GET THE ____ BACK!" but it either comes out or is heard as "GET BACK YOU ____!" Remember, witness memories--just like any of our memories--are not perfect. No one may have noticed what the aggressor did, but they will notice your yell. Is it going to sound (when remembered later) like a warning, or like an incitement to violence?
And what if you just happen to hit a "magic word" that actually gets your attacker's goat, and now he feels he MUST escalate; when a different word would have permitted him to just walk away, and ended it.
Tactically, to me, profanity seems to have more weaknesses than strengths.
I think your notions on profanity have blinded you somewhat.
Well of course they may have--just as your notions may have blinded you.