Mike, no one is discussing whether protestants are Christians, or whether they are in some way members of the Body of Christ. That is a different topic.
This issue here is whether we can say Protestant institutions, their churches are parts of the church. A totally different topic.
I can see a good Baptist who knows nothing but Protestantism and feel they are more pleasing to Christ than me, and trust that He accepts them as in some way united to Himself by their desire, though they have been deceived and do not know they need Baptism to be properly united.
But I cannot look at "harmony Baptist church" or the convention of southern Baptists, and say that this is a part of the Church. It just isn't, it's a human institution formed by people who don't know what the church is.
Bad enough to think you can have a parish that is part of the church without baptism or Eucharist or priesthood. But the biggest issue here ks that HH doesnt seem to understand that the Church is not an institution with branches, departments, parts. The Coptic church and the Ethiopian church are not too parts of the bigger global church. Rather, each local church centered around a bishop is the whole Catholic Church, complete. The Catholic church is all believers I'm all times and places united on Communion with Christ. This reality is manifest in local times and places. It is not an institution with parts. And certainly groups calling themselves churches but not having Eucharist cannot be manifestations of this Communion.
It seems that western ecclesiology is taken for granted, with no knowledge of orthodox ecclesiology. And even then the western ecclesiology is used sloppily, without any careful consideration.