there's nothing that says the rules can't tax the same income more than once.
There's also nothing that says Warren Buffett can claim his dividends are being taxed at a lower rate than his secretary's income.
But you're implicitly agreeing that dividends are being double-taxed. Which makes Warren Buffett a liar.
So ... what's your point about what is allowed or not allowed? If dividends are double-taxed and you're fine with it, that's different than saying dividends are not double-taxed. One is an honest position, the other isn't.