at the end of the day i know fine well the majority of people would do the same and pelt the ball back at them. In most circumstances people would agree with that.. but the extent people have went to, to explain how terribly awful his behaviour is laughable.
I think you might be overstating the case a bit here to be honest. I don't for one minute believe that the majority of people would make the wrong decision and throw the ball at the kids.
The majority would get out of the pool and either have some harsh words with them or get a lifeguard to deal with the situation.
Do you really think the majority of people would resort to violence over kids playing silly (albeit annoying) pranks?