I made sure my brother would never be good at ping pong.
Why don't you want your brother be good at ping pong.
I'm fine if he is good at it, but I don't want him to be better than me.
I understand that you do not want to lose to your brother at ping pong but you should not deliberately make him bad at it so you can win. It is wrong to actively want your siblings to be bad at something.
It's just a silly game. Who cares if he is bad at it?
The fact that it's a silly game is exactly my point. If it's just a silly game, it doesn't matter if you lose to your brother, right? You should be happy to see your brother excel at something!