My 10 year old really made a group of 40 year olds mad

We’re at a local nail salon which was packed and there was a group of 40 year olds having a girls day. Super loud so you really couldn’t avoid over hearing. So they’re all complaining in some form how the guy does bare minimum, wife takes care of everything, gossiping about some other parents at child’s school, mad that ex husband has a new girlfriend, etc etc. I didn’t see this coming but my 10 year old turned to them and said “That’s here say, knock it off. You want to surround your child with that? Grow up. He’s a bum. You picked a bum. He was a bum when you met him and you chose to have a child with him, so what did you expect? You’re gonna get bum behavior from him except now you have two extra people to take care of. My mouth dropped. Right before that the women was talking about how she has to do split weekends with her ex husband and how he has never paid or done anything for her even when they were dating and before babies. He has a new girlfriend and she was talking about she heard a rumor about the new girlfriend and how she has PCOS and probably can’t have kids of her own and that’s such a burden as her only duty as a woman is to reproduce. She also said she’d love to slap her in the face and yes her child was sitting her in lap while talking about it. On drive home she told me she’s been watching a lot of old judge Judy episodes from the 2000s and recited what she normally says. We’ve been home for a few hours and haven’t talked about it since. I do agree that you shouldn’t be bad mouthing the other parent or new parent with the child near by, but idk should I be mad?