Situation without this CPU feature: Cops compromise the ME, disable Boot Guard, compromise your firmware, backdoor your OS directly Situation with this CPU feature: Cops compromise the ME, disable Boot Guard, compromise your firmware, backdoor your CPU so it can later backdoor your OS

There's not really a meaningful difference between these! If there's an exploitable ME vulnerability then the police can absolutely own your system in an undetectable way regardless of whether or not this feature exists. If we were in a different universe where the ME enabled whether or not the CPU was in debug mode but wasn't responsible for any other security features then we'd care about this a great deal more, but as long as compromising the ME already gives you a way to permanently backdoor the system it's doesn't make any real difference.