So I am wondering in which universe is this kind of behavior acceptable? How does this not demean the authority and respect that needs to be given to those in positions above? And how does someone like this keep getting away with it with no consequences?
Maybe in a universe where the authority figure descends to the point of "agreeing" to, by feeding the fuel for and matching the vehemence of, a shouting match with his/her underling.
An argument is a two-way street. A true authority figure should recognize the underling's angst, possibly allow the underling to vent for a bit, but should certainly be able to control his/her own anger and definitely not engage him/herself to the point of a dual shouting match where the authority figure is shouting just as loudly as the underling.
Maybe that's why Supervisor was let go? He/She didn't meet the qualifications for good management.
Another thought:
Maybe in a universe where you don't know all the facts?

A CW of mine had been with the company for 28ish years. He was always a happy person, quick with the jokes, etc. but had his humanly-normal "bad" days, like all of us have. When we got a new boss CWs temperament slowly turned to be a bit more surly.
Whenever CW would talk to me in private, his anger kept popping to the top. Not always about Boss, but the work environment/customers and life in general. This went on as a slow simmer for close to 2 years after new boss was hired.
One day during CW's performance review (believe it or not) CW and Boss's argument came to a head. Major shouting from Boss's office. At one point CW left and slammed the door. Boss ran out after him and said "Get back in here! I'm not done with you yet" . . . more angry words, then . . . "You're FIRED A******!" I honestly thought the two of them would come to fist-a-cuff blows.
BigBoss finally came out of her office and shouted "CW! Go home! Take tomorrow off. I'll see you first thing Monday morning. My office. Boss! Go to your office. NOW! I'll give you 15 minutes to cool down then I want to hear a CALM reason from you as to why you allowed this to happened."
I have no clue if Boss was written up, but a couple of months later CW exploded to me with all sorts of anger (we were the only two in the office that day) about how dare Boss write him up. blah, blah, blah. It seems that Boss had already written him up a couple of times in the past.
I said "CW, this isn't like you. What's really going on?"
That's when he broke down and actually started crying. Long story short, he confessed to me that he had a medical condition for several years now. A certain medication that he was taking warned "There might be mental agitation" (Not exact wording.)
Long story short, I learned why CW had occasional anger fits. I know that he discussed his condition with HR . . . I have no clue if he talked to any of the other CWs or Boss or Big Boss.
I found out that there was much more to the reasons why CW acted the way he did when I heard all of the facts. And, in my opinion? An excellent reason why HR didn't allow CW to be fired on the spot.
DollyPond -- I think your post applies more to the first situation that I mentioned above, but you really don't know, do you? (Yeah, a goat party might be a good point, but I don't like speculating in that way. I'm a give-the-benefit-of-the-doubt type of person.

)
edited to fix punctuation/spelling.