It is my understanding that religious liberty in Orthodoxy is very much seen in a national (ist) context. Orthodoxy as well as Roman catholicism had a close relationship with the secular authorities, but while in the West the States were under the Papacy and the State payed loyalty to it, in the East the Church was under the Emperor and then the Tsar.
In this case, orthodoxy is very much part of a national identity, a devote orthodox christian is always a good patriotic Russian, or a good Greek (that is why other confessions including Catholicism are often listed as "foreign religions", the byzcath Church in Greece, for example).
Other religions were accepted as long as it was practiced by non-orthodox ethnic groups, for example. In that case there was a religious liberty, but unofficially every Russian, for example was supposed and thought to be Orthodox. This is why uniatism is seen with antipathy (in Russia for example). The right of blood prevailed, if your origin was orthodox you were suposed to be orthodox.
In the case of the West, the right of territory prevailed. The 1800's Mexico, at that time a "Catholic Kingdom" (that banned the practice of any other religion) allowed American immigrants to enter Texas and California (unfortunately
) with the condition of becoming Catholics.
But on the other side, Orthodox christians in other places have lived in a status of plurality that clearly didn't exist in Roman Catholic Nations. This is the case of Albania, where there was a natural co-existence between Orthodox, Catholics, and Muslims. (same ethnic group)
