So, your comment is as good a place as any to put this. There's a ton of allegations about ME being a backdoor for the NSA or some other government entity, but very little in the way of good evidence, at least that I've seen. Many proponents seem to provide circumstantial evidence or simple accusations as opposed to what I would consider substantial evidence.

Here's some examples of solid evidence

- Leaked documents either from Intel or the NSA documenting the NSA pressing Intel to provide backdoors, and Intel accepting

- One of the APT groups believed to be associated with the US government is found using an ME vulnerability in the wild, before the vulnerability became publicly known

- Refusal or extreme reluctance on the part of Intel to fix a discovered vulnerability

- A vulnerability which is clearly intentional, like having ME automatically execute any shell script sent over the network signed with a particular certificate or something.

Examples of circumstantial, but still quite compelling evidence:

- A vulnerability which appears intentional, as in it doesn't require any buffer overflow or shell code injection or abuse of certain registers, but rather seems to be a part of normal operations.

- Intel pushes a change to fix an ME vulnerability, but that change simultaneously introduces another vulnerability.

- Evidence that Intel, while giving the US government the ability to disable ME, refuses to give such an ability to other large customers (Google, Amazon, other governments, etc.), for any amount of money.

Seriously, if someone comes forward with evidence like the above, I'm completely open to accepting the possibility Intel ME is an active backdoor for the US government.