How far to go teaching sharing to toddler

[Pickingyournoseattrafficlights]

My DS is 22 months. He doesn't go to nursery but we go to plenty of groups, soft play, role play type places.
I am happy that currently, he is happy to share if someone comes over to use toys he is using, although appreciate that may change as he gets older.
My worry is if I am pushing it too much or not encouraging it in the right way. As an example today, a child came to play close to him and when my DS picked up a toy, the other child snatched it and said, "That's mine." It wasn't but my DS gave it to the child. I said nothing but directed him to play with something away from the other child. The mum said to the other boy, "Oh Bob, you must share," but of course he didn't, as he was just told, not shown to share so carried on.
My worry is by me encouraging sharing, or moving away from someone not sharing, I'm actually going to create a passivity in my DS which may be problematic later on if he can't assert himself.
Am I overthinking it or not?

How do you all encourage sharing and manners?

It’s a tricky balance isn’t it and I know exactly what you mean. I think my view is that we generally expect too much of toddlers as most people don’t particularly enjoy sharing. It’s important but a sense of control is too and I don’t want my two year getting used to the idea that people can take stuff off her, or shove her out of the way, or get in her space and she has to put up with it because it’s her job to be nice or rise above things. I want her to get on with other children and have friends, I absolutely don’t want her to be a pushover. I’m probably over sensitive as she’s a girl and society is currently saturated with be kind bollocks. But the principle still applies.

In the scenario you describe I think I’d have said “no it’s not, DS is playing with it but you can have a turn next”. You can hope other parents will be present, engaged and involved where necessary but often they won’t be and my priority is my child feeling safe and happy.

You didn’t do anything wrong and your son won’t become a doormat by both of letting others children have toys he’s using where that’s the easiest option. But in future if you want to help empower him to stick up for himself then showing him you calmly stepping in will be helpful.

Does any of that make sense or help?

It absolutely does!
I think it just rankles a lot when you are there ensuring your child plays fairly and there are other parents who take the approach of saying something but doing nothing. At this age, words aren't enough and children learn from modelled behaviour.
I shall be more assertive next time if the parents can't be!

Forgot to say thank you also @AnneLovesGilbert.

It is much better to teach turn taking rather than sharing. To a little kid, enforced sharing can feel like 'someone else got to grab my toy' so instead encourage kids to take turns.

This is really interesting! My 24mo doesn't go to nursery and this kind of thing happens to us. I was wondering how to teach her to stick up for herself and what if the other child won't give the toy back when you tell them to?