I agree that such protests are not a good thing to expose kids to but to creating a protest free bubble around every thing doesn't seem practical. As an example it would stop a rally in support of black lives matter as well. Or teachers striking.
Suddenly someone has to say what topics are allowed to have rallies and which are not. We don't want to live in that country.
I'd say the police should handle these differently. For example if the protesters are threatening to anyone in the location but I don't see any evidence that they would make even remotely good choices.
Having said that, the police do need to do a better job. It seems to me that if skuffles break out it probably means there is not enough separation between the protesters. I would also like to stop seeing the police helping fascists too but I doubt I will get that wish.