Hmm never heard of such game to make assumptions…
how: sitting next to your cousin so you can see his cards and across from your brother and tapping your left knee so that he knows what numbers to ask for.
why: you like your brother more and want to pick on your cousin. orrr you want to foster that fraternal connection.
thats the imaginary situation your uncle could have been yelling at, not you.
people are nuts.
I agree with all of that, but possibly in another direction.
People are nuts and so will unite against those that are different and make fun of them. It likely did happen to the cousin multiple times with other kids and when the brothers seem to do it as well, the uncle lost faith in his extended family.
The situation itself might have been imaginary, but it’s most likely an imagination drafted from past experiences.
People suck at times, even ourselves. We should come to terms with that and try to minimize the number of occurrences.