why is it wrong for a primary key constraint to be supported by a nonclustered index
Nothing at all. I don't think I said there was. If I've given that impression it was unintentional.
I do understand using the optional key words nonclustered or clustered adds clarity to action being completed
Yep, that was the beginning and end of my point. I like to be explicit and clear (though evidently I sometimes fail in this regard:doze:)