Perhaps you are not aware that the Bible itself provides for such actions. Consider re-reading 1 Cor 5:5. I guess Paul's Church was top-down, too, by your definition.
I had presumed that heretical priests could be excommunicated by their Patriarchs in the Orthodox Church. If this is not the case, I believe you need to look to why the Orthodox Church doesn't follow the Scriptural precedent. Isn't it the job of the Bishops to protect the flock?
To me, top-down means orders are given from above and followed to the letter in all occasions. There is little autonomy. I see the Catholic Church as being subjected to "interference" from Rome, but the Bishops are relatively unimpeded, unless they are WAY off-base.
Regards