Someone here said that "I don't see how a boy playing with a doll negatively impacts his useful masculine traits, he should be allowed to like what he likes and forcing him to act differently won't change how he feels"

I'll be quoting u/LastRounder's excellent arguement to this statement society can learn a lot from:

Childish games are not only for fun, but also are an educational activity, like games are for all mammals, more complex than a hedgehog.

What you play with is what you learn about. What you learn about is what you are in adulthood.

Playing with dolls affects his masculine traits like this.

Boys are not supposed to play with dolls, that is an imperative accepted in society more or less. So, if it will be known to other children, they will laugh at him, because children are maintaining far more strict censorship and policy of behaviors than any sect or regime would ever able to.

If he gets laight at, that will shurely affect his self-esteem and communication skills in society. Wich in the end of the day is a life changing thing.

He should be allowed to like what he likes and forcing him to act differently won't change how he feels.

Yeap. Also he should be allowed to play with matchsticks. Burns won't change how he feels. A, sorry. They will. And quite drastically.

Same as children mocking him for being sissy because he plays with dolls.

Childish mind is still quite probe to be influenced in that age. So if he switches to boys toys, he will be OK.
If he still wants to play with dolls because of inner will to do so, because he is on the spectrum or something like this, well, he will have a life full of problems. But in that case it us unenvitable anyway.