NTA

but I’m not going to call your nieces and nieces the assholes. They’re just kids and they’re learning. If they’re still at an age where tents full of toys are a dramatic and exciting thing that they get feelings hey over—they’re just acting like normal kids under the age of 10-8 and not assholes.

Their parents clearly are and clearly don’t understand. They’re fortunate they don’t have deal with the added complications of accommodating children who have extra needs beaux’s we they’d probably suck at it if not be brought up on charges of child abuse snd neglect. They failed as parents, adults and being human beings

As i said previously, their children are just that but this was a teaching moment AND THEY FAILED to teach. You can easily acknowledge that it’s not fair but also say, sometimes not everything can be equal and shared. Not everything has to be and and sometimes people just need special places no one else is allowed. The thing you can’t have isn’t something you always need and here are other fun things to do. It’s not about telling a child to get over their feelings but working through it and sometimes learning to sit through inequitable and seemingly unfair situations to them, knowing it doesn’t necessarily do them any harm to not get what they want always. It’s about empathy and understanding when your wants don’t have to be met. It’s a complex lesson that takes years to truly teach a child but it’s never too early to start. I feel like I also need to say—because this is Reddit—I’m not talking about teaching kids to be doormats

Your mother is an AH for implicitly saying Emily doesn’t deserve her tent. But yes—overall—probably it’d be best not to host family things at your place for the sake of comfort. Your siblings are clearly not going to parent their children.