The question wasn't "why do protons have +1 charge", it was "why do protons have +1 charge, *considering electrons have -1 charge". The fact that possible charges are restricted to a few values is a much more satisfying answer to the latter than the former
> deflects the question one level down without explaining anything
There’s a lot of levels to SOC. Which do you think is “because it is?”
If you’re asking why spin values are restricted, it’s in the spin-statistics theorem [1]. If you’re asking why spin causes charge, that’s SOC. There are lifetimes of understanding contained within those layers.
"Because it is" is not a helpful answer to "why?"