EDIT to expand a bit since some people seem to be missing the point: hypothetically, GP might have preferred Intel on narrow technical criteria, but have been willing to override that preference for the sake of transparency. No transparency difference, no reason to override.
Fwiw I'm not ready to use open-ish ARM/POWER exclusively, but AMD/Intel'll have to contend with that soon(tm)
[Answer to parents EDIT] I'd argue the effective technical difference set between AMD & Intel is growing ever narrower, and aside from brand fidelity there is very little reason for a consumer to have non-moral preferences to one or the other manufacturer.
> https://www.crowdsupply.com/raptor-computing-systems/talos-s...
Because Intel's ME/AMT sure as hell isn't any better.
It is not attached to ARM's CPUs, not it is mandatory, it is just something that SoC developers can pick up and implement however they want.
Still, some boards/devices may lock it down, for example by code signing.
If you are making something with the SoC.. it's probably safer to buy the locked down version of the SoC than to mess about with TZ or to leave it open.
The CPUs from Intel/AMD are much more than a simple CPU, they are a complete system on a chip with a lot of more features that go beyond processing power for your system. On the other hand, an ARM CPU is just a simple CPU.
If you want to make comparisons, a more correct one would be between the Intel/AMD CPUs and a Snapdragon processor.
AKAIK, only the Versatile/RealView style boards that an SoC manufacturer would get directly from ARM come with bare ARM chips. Anything other than that is an SoC.
My point is that an Intel/AMD product is a complete solution while an ARM product is just the very basic implementation of a CPU.
ARM doesn't mandate on anything related to the SoC except for the CPU, everything else related to PCI buses, memories, physical implementation, chipsets, etc, is up to the SoC developer to decide and implement.
There's simply no way to get a completely trusted computer stack nowadays, short of assembling it by hand using discrete electronics. It won't run very fast though...
I guess an alternative would be to crowdfund the production of an open source CPU then take a few samples and send them to people with an electron microscope and a lot of patience to make sure that the silicon really matches the design and wasn't tempered with in the fab.