AIBU to think that I'm a cowardly shit not to call a mum out in a shop for being extremely aggressive to her kid?

[DonkeyHotei]

So I'm in a tiny pharmacy, a queue of 6 or 7 people at the til and a mum (presumably a mum) comes in with a pre-teen boy, sits him at the seats by the door and then proceeds to speak to him in the most aggressive manner imaginable about not touching the button with the wheelchair motif on it, the one which potentially opens the door if you're in a wheelchair. He hadn't actually touched the button; it was a pre-emptive in case he did. But the way she said it was so unbelievably aggressive: loud, with real anger, threatening language, swearing etc. As I left the shop and drove home, I thought about all the things I could have said: "why are you speaking to your son in such an aggressive way? ....it sounds really horrible and frightening for him....I know i can't stop you from speaking to him like that but I am allowed to have an opinion on it (or am I?)....the way we speak to our kids directly affects the people they will become, and if you bring him up with aggression like that, and as a result of that he comes an aggressive adult, then society as a whole bears the brunt of that. Furthermore, if you unashamedly speak to him like that in public, God knows how it is behind closed doors..." etc. etc. But instead I said jack-shit, mainly because I'm a coward and didn't want to interfere in case that would be embarrassing for me. Is it acceptable/desirable to stand up for the weaker members of society when they are being (what seemed like) bullied? Or is it none of our business? And if it's none of our business, where is the line drawn: if she hit him? Of course I do get that she may have been having a bad day, he may have been playing up etc and she was at the end of her rope etc. But the level of aggression directed at this boy seemed really inappropriate. WWYD? Thoughts?

Good point @gingerrogered. If it was actually bad enough that it spills over from "normal, stressed mum" into "abusive" then (given it was a tiny pharmacy) there will have been CCTV in the shop viewing the whole thing, and other people, ie chemist staff, can help make that call. So it just remains to see if I have the courage of my convictions to go back there and mention this whole thing and get them to check. And I think, rather than just feeling guilty in the aftermath and posting this on mumsnet, that would be the thing to do. But...but...it's not easy, as the very idea of going in there and asking them to do that makes me feel mortified...

Arggghhh....problem is, I think it was bad behaviour, but I don't think it was illegal. There is no way I could actually go back in there and ask them to do something about it from a CCTV. That was a stupid thought I had just there (I mean a stupid idea on MY part, not on Ginger's, as I think it would be a good way IF the situation had warranted it, to follow up in that way....)

Totally agree with @Branleuse on this. You cannot judge a parent by witnessing one minute of their day.

You can certainly judge the parent's bullying behaviour, because that's exactly what the OP describes.

As I said in my example, I'm sure if you had been next to my family in the queue at the carnival that night then you could have assumed my Dad was a terrifying bully - he wasn't. As PPs have also said, there are many circumstances that could have led to that and does not mean this parent is like this all the time