Why do Catholics have to have a Bishop present for Confirmation, but we dont?
Orthodox don't have a rite of "Confirmation" (which is something that typically happens to Roman Catholic tweens years after they have received their first Communion at age 7 or 8 and then undergone a period of religious education).
Orthodox, on the other hand, have one, integrated rite of Christian initiation, including Baptism, Chrismation and then Eucharist (with several other ceremonies thrown in all at once). Some texts speak of Baptism as a personal Pascha and Chrismation as a personal Pentecost, leading immediately to full incorporation into the Body of Christ as a partaker of the Eucharist. There is no sense that these sacraments can be spread out over 10 or 12 years. A baby or a convert is made a Christian and a full member of the Church, right from the start.
In some comparative manuals, one will see the claim that RC "confirmation" = EO "chrismation." It's only true in a very attenuated, historical sense. The two practices have developed into very different rites with different theologies.