Yes processors run microcode.
But that is no reason to connect it to an antenna which allows a pc which is turned off to still be able to run wireless remote management commands.
In security one of the most critical consideration is to reduce the attack surface.
Intel vPro/AMT has such a large attack surface, that if we can assume there are no deliberate back doors, it is a safe bet that having it still introduces a wide range of new attack methods against us.
And for what? Just to help make corporate IT's job a bit easier? And remember those extra gates to support it does increase the chip's die size, power consumption, and cost.
Why not have AMT/vPro only in corporate PC's on request, and not have it in anything else.