Sharing is joining in and sharing the same toys, not snatching it out of hands! Children are all learning and need their adults' help with these kinds of things, so the mum was completely in the wrong there. She should've guided her child to say there are plenty of the same toys around and he can sit and play with the same ones, but snatching from another child isn't okay. Sorry you were in that situation, it's okay to feel the way you do, but you weren't in the wrong! X
I hate parents that try snapping on the adult for childrens actions. Like no!!! Teach your child at home or one on one how to behave. Even if you were wrong which you weren’t. If that were my kid, I’d just move them away from the entire situation to avoid any drama from moms like her.
That other boy was wrong taking something out of your little ones hand. That is not sharing that is snatching! When that happens again, stand your ground and explain to the play worker that your boy is still playing with that item. The mom will sing a different tune if you go up to her and take something out of her hand, saying she has to share...