Hello99,
The Shach clearly says that Stam Yainam requires some connection to AZ.
We can go back and forth on this ad infinitum (ad v’lo ad bichlal 🙂 ), but he says no such thing.
I haven’t ignored it, I’ve said I would rather ask him personally rather than rely on a teshuvah in which I don’t know the context.
R’ Moshe clearly personally felt that it was only based on chasnus, yet in his teshuva never clearly paskens to be totally matir, in fact apparently only wants to rely on it with a tziruf.