DD hurt by older cousin

[Zoono]

I need to know if I'm being a silly ftm but whilst playing in a outdoor play area ( only children in the play area) my DD and niece where throwing bark/ dirt everywhere. Told repeatedly to stop by myself and Sil. DN stopped doing it sooner but she is 8 compared to DD who is two. Eventually DN got in DDs face and told her loudly to stop. DD slightly pushed DN a couple of times. Before I could stop DD , DN grabbed DDs hand and smacked it. I never physically discipline DD so she was understandably shocked and hysterical. My main issue is DDs auntie simply said she was relieved DN didn't slap DDs face instead and that she used to smack DNs hand for similar behaviour. DN in general is very hyper and never disciplined by her mum , which other family members have witnessed. Aibu to be really hurt by DDs aunties lack of compassion to DD. For context in my own family, people would be horrified to see an older child deliberately hurt a younger one. DD has never pushed her cousin before today or tried to hurt her at all and I will tell DD off , for being pushy with other children when she occasionally tries to push them.

Yes tbf, I wouldn’t have left them throwing stuff around in the first place.

If DN has had her own hand smacked before I am not sure where you got the her parents don’t discipline her … just unfortunately not in the right way

Why didn't you stop your DD from throwing sand? Yes, the 8 year old should stop when told - which she did - but if th e2 year old didn't stop, why didn't you go in there and stop her by removing her? Obviously, your neice's response wasn't ideal and she should have been stopped too but I think this is a classic issue of someone not managing their toddler's behaviour and then expecting an older child to somehow be more adut about things.

I feel quite irritated on behalf of your SIL frnakly.