I'm sure this is illegal and AMD should be prosecuted for it. The people who decided to implement these "security" measures should lose their jobs and/or face legal consequences for it.
If they did such a thing with car components, it would be shut down in no time. No different for computer parts.
Also a CPU that can be rendered permanently inoperable due to a software issue could be considered not fit for purpose and thus a defective product. Especially if it was intentionally designed this way - such that the CPU can self-cripple itself.
Maybe a legal firm would want to take up a class action against AMD for this potential product defect? Viruses and malware should not be able to physically destroy a CPU. There should be physical hardware protections against such destructive behaviour occurring due to a software induced logic error.
The PSP is not truly secure, someone should write a PSP eFuse bricker tool (Ryzenkill?) that can be run as a proof of concept to show the CPUs are defective, and then we can have a recall or free replacement of the CPU by AMD. I'll look into it myself - I need to ensure it's legal for me to write it from the country that I'm residing in right now. I personally have extensive experience hacking older AMD processors and GPUs through JTAG.
I'm sure it's still legal to provide a list of addresses and data writes that you need to perform to permanently brick the CPU?. I don't think that is classed as a "hacking tool". I can get t-shirts printed with it on, together with the words "AMD Ryzen CPU Self-Destruct Sequence". I don't think selling those would be illegal?