Yes but that isn’t the main point. When combined with a non-free OS TPMs become a tool used against the user to lock them out of their own system.

You are right. The problem however is not in the TPM but in the non-free OS.

Thanks for the link, I wasn't aware of Purism's work in this space.

Is an open and flashable TPM something rights holders would be comfortable with? Or would they treat it like SafetyNet treats an Android phone with an unlocked bootloader?