I assume that Apple's reasoning is similar.
To head off: it's not the patent grant. Apache 2 has a very similar patent grant and everyone is fine with it.
Edit:
Here is more information about that:
> Protecting Your Right to Tinker
> Tivoization is a dangerous attempt to curtail users' freedom: the right to modify your software will become meaningless if none of your computers let you do it. GPLv3 stops tivoization by requiring the distributor to provide you with whatever information or data is necessary to install modified software on the device. This may be as simple as a set of instructions, or it may include special data such as cryptographic keys or information about how to bypass an integrity check in the hardware. It will depend on how the hardware was designed—but no matter what information you need, you must be able to get it.
Source: https://www.gnu.org/licenses/quick-guide-gplv3.en.html
That means if there was GPLv3 code in iOS, Apple would have to send you their private keys to sign any source code so you can run it on iOS.
"The reason we can't ship modern Bash on macOS is that we're concerned we might accidentally include Bash on iOS."?
(and /bin/sh on macOS is already sufficiently user-modifiable to satisfy GPLv3)
OpenBSD apparently isn't fine with it, fwiw.
> The original Apache license was similar to the Berkeley license, but source code published under version 2 of the Apache license is subject to additional restrictions and cannot be included into OpenBSD.
> -- ref: https://www.openbsd.org/policy.html
I understand that you're well-intentioned, but I find the suggestion that I'm somehow not informed to be rather patronizing to be honest.
"There are restrictions!" "What restrictions?" "Everyone knows. It's patronizing to ask me. I won't say."