We could just call all those orthodox folks who acknowledge their salvation by the shed blood of Christ, as described in the traditional Creeds, as “Christians”.
Yes, they are, but the discussion was about what was encompassed by the term referring to non-Catholic Christians, that is, Protestants. Catholics and orthodox creedal Protestants are Christians; we can’t refer to “Christians” and “Catholics,” although I know there are some on FR who do, unfortunately.
There are many different kinds of Protestantism, some of which are Christian only in the sense that they’re not explicitly anything else. But they all refer to themselves as Protestants, even though some of them have split off so far they’re in outer space.