I believe that all Christians did not, and that Christians were not the majority. Most "Christians" may have. You have to remember that conversation via compulsion is never a good idea. This is how the Catholic Church came about. We see this in Vodou, Santería, Rastafari, etc.Do you all think that Christians started supporting war after they became a majority in the Roman empire? If they wouldnt have served in the army, they would have been stomped… much like the Orthodox church was later by Islam.
Over time Christians accepted political involvement as normal because of thar blend of Christianity and political life (Church and State).