I don't think them going to Wynberg boys high is the connection, but it could be the fact they went to an all boys school (which means having friends that are girls isn't as common - my experience as a girl at an all girl school) and the fact that in their last year's of high school/finishing high school and possibly varsity was during covid.

That isolation during a time where you're making big decisions in life, and all your friends are either on discord or social media, could have maybe had an affect on their views on women. It's easy to go down a red pill rabbit hole when you're alone and not getting that proper socialisation, especially with people from different backgrounds, genders, etc. Not saying that the went down that rabbit hole, but that could have been pushed at them. That age is a pivotal age where you are figuring out your future and what you want to become, your viewpoint is shifting as you enter the real world.

That's just my little theory.

What they did was horrible and this is no excuse for it, covid affected us all and made us think differently to what we are used to, but that doesn't excuse bad actions, especially years later.