Where I live if someone bumps into you both parties say "sorry" about 80% of the time
Exactly. That's how Canada rolls, most of the time. And normally the person who was bumped into will say "that's okay" or "no problem" after the "sorries". The words tend to be spoken quietly and calmly, and the situation does not escalate.
There have been times when someone has bumped into me, apologized, and then asked, "Are you okay?" because they want to be sure I wasn't hurt. If I'm carrying stuff (as happened a few times before my walker became my extra pair of arms and legs and I was using canes - which are really awkward when you have groceries to carry as everything needs to be balanced), there were a couple of times when they offered to help me.
Those were nice, considerate people, and it's a shame that there are others who are not considerate.
That said, I have felt irritation at being bumped or pushed past and the other person did not apologize. I don't go into full BS!C mode, though. It's annoying, especially so if it does result in being hurt by being pushed against something like a wall, or off-balance. Balance is so important when you're using a mobility aid, because you can't react as quickly - especially if there's not much room, or the surface you're on is uneven or slippery.
So what happens the other 20% of the time?
My guess. 19% no incident happens and one or both parties assume they’re rude. 1% physical altercations.
That's essentially it. Sometimes people exchange angry words. This can happen when someone's blocking your way and won't move after you've said "excuse me, please" (which is polite Canadian for "you're in my way, please move"). If they don't move, I assume they might not have heard me as my speaking voice isn't that loud, and repeat myself louder, but still politely.
If they
still won't move, I just tell them that I would like to get past them. If that doesn't work (it's unusual for things to get to this point), I am past annoyed and beginning to get angry. Please note that these are situations where they have room to move. I don't.
Things got really annoying the time a couple of women decided to stop for a gossip in the aisle of the grocery store and were blocking the view of the shelf. The custom here is to move when you notice someone looking at the shelves, especially when they say "excuse me". On the occasions when I don't have a choice except to move between someone and the shelf when they're looking at it, I always say "sorry" for blocking their view and move as quickly as I can.
These two didn't, after repeated requests. Finally I just said, "You are blocking me from getting the things I want. This is not an appropriate place to gossip, so would you please go somewhere else, like a bench or the restaurant." That's not actually as rude as it sounds, btw, as they had been standing there for about 20 minutes, while I was circling that area of the store trying to find what I was looking for (peanut butter) and not finding it; a stock clerk couldn't find it either, and then I realized I couldn't find it because they were standing in front of it - and would not move more than an inch, which was clearly not enough.
Thing is, though, at no time did the situation become violent. I was getting pretty exasperated by that time, as these two had bumped into me earlier and knocked something from my basket onto the floor - no apology, no offer to help pick it up like anyone else would have done. So they were already on my <censored> list.
I realize that this must sound crazy to some people here, but I'm describing Canadian Grocery Store Manners 101. The bit about blocking someone's view of a shelf and getting out of the way as fast as possible and apologizing also applies in other places as well, like bookstores, libraries, and many other places where you have people browsing what's on the shelf in front of them and someone blocks the way either accidentally or is passing through because there's no other way.
(I've been told by some Americans that they never say "please, thank you, or sorry" because it sounds like begging or groveling - and saying those words would hurt their pride. I can't wrap my mind around that attitude.)
I mean... the white woman even apologized to them, despite being called "ignorant" (sic, what does this even mean in this context...) and "b****". Then they had to continue and do stuff like get the plate number for whatever dumb reason.
We can't stop here, this is bat-stupid country.
"Ignorant" has multiple meanings, depending on context. One is "doesn't know this information" and another is "stupid/idiot". Yet another is "hostile". The teenager likely meant it as a combination of the second and third examples.
They wanted the license plate number to tell the cops so they could find and arrest the couple.
I found it interesting in a

way that it was the mother who was throwing around threats and racial epithets like "yo' white ass" when she was screaming that the woman in the car was racist. There were other epithets she used, so I guess this only works one way?
If someone could post the video I linked (I don't know how to post a news site video), those here who haven't checked out the links can see the couple's side of the story. It turns out that the mother had two daughters with her, and by the time the gun was pulled there were numerous people coming toward the couple in the car, and the woman genuinely felt threatened.