Because the owner of the other class of share believes themselves to own part of the company, but they don't. It's confusing. What you really own is some sort of bond from the company that guarantees they will pay you an amount equivalent to a dividend or something, not a share of the company.

> Because the owner of the other class of share believes themselves to own part of the company, but they don't.

Shares, whether in one class or many, are packages of claims against the company, not really ownership of the company in the simple sense. That’s fairly fundamental to the corporate form as distinct from, say, partnerships.

Because shares express ownership, and ownership is defined by being able to make decisions about the owned thing.

both BRK.B and BRK.A have voting rights.