I taught in all boys schools a while back, for a few years.
Some of the games played in fun where really quite physically & psychologically aggressive. Boys used to get hurt. Occasionally quite seriously.
I really felt for those boys with gentler natures. There seemed to be little escape from it. All they wanted was to be left alone, to be left out of such games. But mostly they weren't.
(I am just waiting for someone to turn up here telling us that such games are good, manly, character-building activities. Good for boys. And that we are a bunch of mamby-pambies for expressing any concern. What do you reckon?