It's interesting that you say that, because the cop was accosting this women, and then once the husband arrived the cop then stepped toward him in a threatening manner. Only at this point did the guy push him away. So when a civilian feels physically threatened and pushes someone away it's not self defense, but when a cop gets pushed and he draws a firearm, it's "diffusing a situation?" And please, there's no need to get pedantic and say, "but but, the cop didn't actually touch the civilian, but the civilian touched the cop!!!!" If you can't see the grey area here, perhaps you are the one that needs help. You're correct in your assertion that a cop has right right to voice his displeasure, even in a rude manner, however, he does not have the right to accost someone else, nor act in a physically threatening manner - two things which he did.
Accosting a person? Wow, nice use of vernacular to make it seem as if the cop was doing anything more than voicing his displeasure at her rude actions. If I'm in line behind her and say something as rude as "Hey you fat bitch, go to a different lane as this is the express lane" then that is not "accosting" her as you put it.
Now if the cop said to her "I'm going to break your fucking legs you fat bitch if you don't move" then that is accosting her. Do you see the difference? From what news I've been able to glean he did nothing of the sort. The cop never threatened any form of physical violence to the couple until he drew his gun.
So no, being rude and calling someone a name is NOT the same level as being physically assaulted.
However, I am not saying this cop didn't make a physically threatening gesture first. The only claim to that is the man who shoved the cop saying the cop step towards them first. We have one side of the story and not the whole story either based upon that article.
Again, if the cop only voiced his displeasure, regardless of how rude sounding it may have been, it does NOT give a person the right to shove that person for sounding like an ass.
In this case, I am going to take the position of the cop's side, unless I get further evidence such as eye witness testimony that does not include the two parties involved, that state which party was doing the physical threatening first. If it was the cop, then he was in the wrong. The guy has a right to defend himself and his wife against perceived physical threats.
If it was the black guy on a macho trip trying to get physical with someone he saw as smaller, weaker, and being an ass at the same time then no the cop was not in the wrong. Experience has led me to be inclined to believe the second scenario I just listed though, although that may not be the truth. I think the reality is the cop said something the bitch didn't like without the cop actually physically threatening anyone. When the husband came back, the bitch probably egged the husband on to do his stance on dominance on the cop, who she didn't know was a cop, just because she married some big guy. Then the whole situation back fired when they realized too late they were physically threatening a cop who pulled his gun out on them. This scenario is typically the reality far more often than not in a situation like this.