It doesn't matter if it's a deliberate backdoor or not. It's a door, and I want to be able to close that door if I'm not using it, and Intel won't let me. Reducing attack surface is a security best practice exactly because any software can have bugs.

An allegory: imagine if an OS ran an SSH server and there was no way to turn it off or to control the keys it accepts. Maybe it has no bugs (you can't see the source code). Maybe it has no malicious intent or backdoors. As a security conscious computer owner, I still view its existence as a negative. I would like to be able to provably turn it off or control the keys it accepts.

And that's exactly what matters and why I among many others call it a backdoor.

Telnet on the other hand is a service that I can switch off or block with far less work involved in normal circumstances.

To get rid of Intel ME I'd need to use Core-/LibreBoot and install it in a ritual that for a novice has something of a "black magic rite".

Forcing upon users is wrong but calling it backdoor, as someone who sounds reasonably intelligent to other reasonably intelligent people is misleading and wrong too.

I think this is one of those cases where you need to take into account the intent of the Intel ME and whether or not you can consider it a backdoor. Surely it's a useful tool in corporate environments but to any other average individual it's definitely a backdoor. It's a "feature" of nearly every modern x86 CPU that undoubtedly has capabilities of a backdoor that cannot be turned off or disabled by regular means. If I wanted to be able to remotely manage my machines out of band then I would've asked for it, but instead I foolishly bought myself into a very easy way for vendors to maintain control over me and my data.

A backdoor is access to a computer which the legitimate owner cannot control. Intel ME fits this very well. Let me switch it off (verifiable) and we can talk.

If it was for troubleshooting enterprise computers, it would be opt in. At this point I assume bad faith.