It's not possible to know who Christ is without the Church so any protestant who is a christian is a catholic even if they don't know it. They reject the authority of the Church but accept the authority of the Church when they accept the orthodox understanding of Christ.
This is the way I have looked at things. That all those separated visibly from the Orthodox Catholic Church, whatsoever is of the truth in their communities is a witness of the presence of the Holy Spirit as He wills, and is a tenuous bond with the Orthodox Catholic Church.
If they are Christians, and if I am a Christian, then it is because of Christ. But that judges me as well as them.
It is not so much a theoretical distinction which may or may not be of value which I dislike - but it is saying in people's faces 'You don't believe in the same God as us'. If that is so then as an Evangelical I would have been deeply offended and could only consider that I must be accused of worshipping demons.
I know that I do not deserve the name of Christian so how can I spend time insisting that this group and that group are not Christians. On the contrary their lack of knowledge makes them much less liable to condemnation than I am.
I still find speaking the distinction out loud to be condemning, and counter-productive.
Why say it? Who does it help?
If anyone should be judged not a Christian I know that it is ME!