But my point OP, said with genuine positive intent rather than to make a point, is that you jumped on the first poster, taking an extreme interpretation of their comments and making it quite explosive.
They said your son sounded rude and entitled (which is not an unreasonable position to take from your OP, though I think your later posts correct that framing), and they also said that your nephew needed speaking to as well.
Your first reaction was to say: “So what I'm hearing is despite that when I take an explaining tactic 9 times out 10 he does actually take on board what I'm saying but now when he has attitude I should scream in his face instead and that should do the trick?”
Nobody was saying you should scream in his face. It escalated way before you then got a later pile-on.
I mention this not for some gotcha moment but because it’s a really defensive reaction, and I wondered if that vibe had carried through into your real life interactions with your family.
for clarity, I don’t think anyone should ever scream in someone’s face and it’s a sign of emotional immaturity and a lack of emotional regulation. We are all human, of course, but adults shouldn’t be doing it and your Dsis should apologise.
But your reaction to any different perspectives is also quite extreme