Make your password longer then? It's about entropy, not the symbol set. In practice, one could remember to "put a dot before uppercase", or some other encoding notion (hitting shift does not save on keystrokes either). One might be able to memorize longer passwords when the case is unimportant. And the "horse staple battery" thing? It's essentially chinese block characters, spelt out in english. You have no convincing argument.

Remembered pass phrases are not well suited for strong access protection. Slow to enter and hard to remember.