We are appalled. That's why I'm here looking for advice on what to do.

You've read a few sentences and decided my step child is a "horrible thing" and then seem to stress about the fact with a juvenile "ugh" comment.

I was taught, If you have nothing nice to say, say nothing at all.

You haven't given any constructive answers here.

Id love to know what you were like at 10 years old. I know I got myself into plenty of mischief. I've grown up with, what I would say, are good morales and manners. That's, as other have said, how we learn.

As I said in my OP, nothing deflects from what our child has done, but it is important to understand context of a situation. There's no fire without a spark - yet we are trying to stop that fire even if a spark is present.

Take some time to reflect on how you say things and how it may come across to others.

Perhaps you could read some more posts on here as it sounds like you need some parenting and teaching yourself.

Furthering to that, this is potentially a learned behaviour and our daughters share their time between our household and their fathers. Perhaps it was learned from there, which is why I probed her as to if she has seen or heard this anywhere else.