If my kid doesn’t care I don’t make a big deal about it. I feel that would do more harm than good cuz they would learn that they were rejected or teased, whereas as is they don’t care lol.

I do interfere if some kid is being unfair to my kid in a way that does impact my kid. E.g. a 7yo girl took my toddler son’s toy in the pool and then he took hers because he thought they were playing together. Then the girl started insisting he give her toy back (but she kept his) and saying to me that she didn’t want him there and to get him to leave her alone. Well of course in that context I had to take action, so I told her that if she’s going to play with his toys it’s only fair he gets to play with hers or that she include him. She then gave him back his toy and left him alone lol.

I think it depends highly on who the other child is, and the exact circumstances. I personally think older kids should know better than to take things and to exclude others for no reason.

I do kinda have an issue with the modern view of “it’s Ok for kids to tell others they don’t want them there and to leave them alone.” Cuz it’s a slippery slope of exclusion and meanness.