Ok, lets put it this way,
If, at playgroup, (or in a cafe) a 2 year old wipes your 1 year old around the face with a pencil case, causing a broken nose or a cut, do you then beat the older child half to death or do you tell the parents to control their child?. That, in effect is what you are saying.
If in Asda's and another couples 3 year old from his pushchair screamed loudly at your child in a pushchair in the next queue and set them off (they do it quite often TBH) would you run up pushing and screaming at the other parent's that he should be in an effin cage, drive them out of the shop and then act aggresively in the carpark to them?