I seem to remember somewhere in the Shahnameh some mention of Christians, complete with their bishops, showing up on the field of battle. I definitely know Erasmus had an unkind word or two to say about such things too. But it seems to me 'thou shalt not kill' and Christ's blessing of the peacemakers would be enough to condemn this.
There are a range of insults a modern person could suppose might happen in a phyletist church, but to an ancient christian, these insults would be sins against hospitality, and have little to nothing to do with any sort of institutional racism.
The term phyletism was coined at the Holy and Great pan-Orthodox Synod that met in Istanbul (then Constantinople) in 1872. The meeting was prompted by the creation of a separate bishopric by the Bulgarian community of Istanbul for parishes only open to Bulgarians. It was the first time in Church history that a separate diocese was established based on ethnic identity rather than principles of Orthodoxy and territory.
On 10 August 1872 the Synod issued an official condemnation of ecclesiastical racism, or “ethno-phyletism,” as well as its theological argumentation
We renounce, censure and condemn racism, that is racial discrimination, ethnic feuds, hatreds and dissensions within the Church of Christ, as contrary to the teaching of the Gospel and the holy canons of our blessed fathers which “support the holy Church and the entire Christian world, embellish it and lead it to divine godliness.”
The importance of the old standards have, undoubtedly, been subsumed by the new anti-racist standard. In the West, churches of every denomination have been badly effected by the revolutionary movement and the subsequent dysgenic effects on IQ over the years. It is doubtful the East is immune, though I do believe the relative anarchy largely kept doctrine and liturgy untouched.
I have a dim view of modern nationalism. I believe Bismarck basically destroyed Germany in order to create the modern German state. There are, however nations, and the Bulgarians may have been responding in self-defense more than anything else. I don't know. Google searches on this are a bit frustrating.
People of today tend to have a disordered view, and it can be seen in the lack of family formation, misguided evangelization adventures, and the tendency to assume European civilization can run just as well if you just plug a bunch of other warm bodies into it. If there is no Christendom, there is no place to live as a Christian.