Their goal/feature/product, whatever you want to call it, is to create something secure enough that grandpa can’t get tricked into getting owned. Anything at all that allows people to disable security becomes an immediate threat for that type of user. If the side effect is that they prevent people from jailbreaking then so be it because they have no desire or obligation to support those users.

Yes, let's add a potentially system breaking switch to a consumer phone.

Believe it or not, the world doesn't revolve around the software geeks.