It's not an issue of permission, it's an issue of trying to make a computer that's safe for grandma to use. Criminals can and will convince grandma to navigate a byzantine labyrinth of prompts and technical measures in order to drain her bank account. That's the threat model we're dealing with here.

And you don't. THIs is not iOS, gatekeeper can be bypassed if you know how.

…you don’t, just like you don’t need the bank’s permission to withdraw funds… but they will still try and stop you pulling out $10,000 so you can buy iTunes gift cards to pay off your taxes.