cathar
Do you have a reference one can actually look up?
What is being suggested here, indirectly, is that the FAA Class 3 is non-ICAO but the FAA Class 2 is ICAO.
I do know that the FAA Class 3 can be non-ICAO if it has certain restrictions on it. This doesn't mean anything, because the CAA or any other national authority can do the same. Such a concession makes the license valid only in the country of license issue, and in countries which have accepted the concession. It is up to the holder of such a medical to know his rights, as usual.
I have no axe to grind since my medical isn't Class 3.