The GP is simply wrong on many/most of its technical claims. ACPI implementations were common for 4+ years before the ME existed. The ME is not involved in DRAM refresh or initialization at all (other than waiting for it to complete..). DRAM refresh is hardened into the IMC, and the initialization SW runs on the x86_64 cores - typically it's a UEFI binary blob provided by Intel. Once the OS is running, it manages the IOMMU, and the IOMMU itself is a hardened function; the translations that it performs for the OS do not involve the ME. And so on.

Though the ME currently performs some complex early initialization tasks, the notion that a modern x86_64 platform simply cannot work, or cannot work efficiently, without the ME running indefinitely/alongside the OS is plainly wrong.