Children have the remarkable ability to see the world as it truly is, and so are able to ask the most profound questions. As adults, we learn to obfuscate our, ah, knowledge deficiencies in various ways, and so lose that ability over time. I'm of the opinion that great physicists are like children in being able to see through to the heart of the matter, and ask -- and answer -- questions that matter. This is certainly a theme you can see with Einstein, Bohr, Feynman, and others.
Why do I say this? Because GP's question was profound, and saying "it's because charge comes from spin" is the sort of obfuscatory answer I see most physicists give very, very often when they're faced with such questions.
That's completely aside from the fact that "it's because charge comes from spin" is entirely incorrect. All charged particles have spin, but not all particles with the same spin and other similar properties are charged.
If you refuse to ask further questions, yes. If you keep asking why, it opens the door to what charge fundamentally is.
> All charged particles have spin, but not all particles with the same spin and other similar properties are charged
Spin and charge are fundamentally connected. That said, I was answering according to SOC, which remains a hypothesis.
"Because it is" is not a helpful answer to "why?"
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.
According to QED's spin origin of charge, it's because charge comes from spin. What values a particle's spin can take are restricted to certain integer or half-integer values.