I have read all 6 of the links you posted above and NONE of them claims that WMP reads or writes to the POPM tag.
I don't know what else to post, there's plenty of evidence that WMP saves ratings to files (which is not relevant anyway, the point is that it reads POPM in a non-standard way).. not that any of that matters because whatever I post you don't believe, though I've posted hard evidence.
You could post ONE specific, verifiable example of what you claim to be true. Just one.
I have challenged you to provide evidence of the "De-facto POPM implementation" which you claim exists, but you haven't done so.
You could do as I have done:
1. Make a claim, that someone else could test, such as:
"WMP v12 writes worst rating as 0x00 POPM field, and is therefore compatible with MediaMonkey"
"WMP v11 reads 0x00 from the POPM field and displays 'worst' rating, and is therefore read-compatible with MediaMonkey"
You have done neither so far whereas I have provided proof that the second is NOT true (WMP v11 is NOT compatible with MM, in reading 0x00 as 'worst').
You could post links to pages that actually make claims, and provide evidence about POPM compatibility.
Furthermore, all the stuff that you have cited in the MM bug database also fails to give any detail about exactly how MM claims to be 'compatible'.
2. You could post a list of steps to reproduce whatever claim you make.
I have done this for my claims, such as:
"MediaMonkey (latest version) is not compatible with id3v2.3 POPM specification"
I have cited the spec as proof, as well as experimental steps to reproduce, include exact byte-for-byte hex data
You have claimed:
no one else follows the spec either!
I have refuted your claim already in this thread, showing exactly how J River Media Center is compatible.
I have also shown how WMP11 is compatible with id3v2.3 POPM spec and that MM is not.
I have providing steps to reproduce, including hex data from MM, JRiver POPM frames.
This is the type of thing that is needed: facts, not hand-waving or unverifiable claims.
Why don't you just tell us exactly what is this "De-facto POPM implementation" that you claim to be compatible with - be specific in terms of star ratings and POPM data.