I´ve heard many orthodox priest commenting on Christ words on this same theme. That no one needs to be called father, teacher or any other thing out of pride, that you lift up yourself because you are a teacher, a father, a pastor, a priest, a mother etc.
If Christ only meant for us to condemn the use of these 2 names, whereas we use both in our common language. Can we still call someone high priest in the light of an none orthodox tradition? If Christ gave us this strict command not to use only these 2 names, then we have to consider all the other names he didn´t mention. Can someone within a church be called king? Queen? Dracula? Christ never condemned the use of these, so then it must be okey. But in the light of these names being used as a mark of pride, then many other names are suddenly included.