I'm all about hating on the psychiatry profession, but I believe what may be missing here is that these diagnoses are always optional.
If you like your grief, you can keep your grief. But if you need help, the criteria need to be there for you, for insurance companies, employers, and such to systematically do all their accounting and such.
It's a bit similar to a lot of controversies around the autism spectrum. If it's just a personality quirk and you're a functional adult then it doesn't really matter if you meet the this or that criteria. If you like your autism, you can keep your autism.
Immigration and assimilation policies in the west have been too rapid, faster than even those who think they're open minded can adapt to new people.
The result is a pervasive societal siege mentality with everybody retreating into their homes. The Starbucks data on where "third places" are thriving or dying aligns very well with this model.
The answer is as obvious as it is unwelcome, which is it slow down a bit and give people and families time to adapt to their strange new neighbors and neighborhoods.
We lack the moral courage to be honest about why real world community disintegrated and are therefore doomed to suffer these pedantic lectures that miss the point and point in random directions.