The church did not decide that after the schism to my knowledge. There was an Ecumenical Patriarch who wanted to suppress the Divine Liturgies of Ss. Mark and James, and who issued orders to this effect, but these have been widely ignored, and those were Eastern Rite liturgies. As a rule I don't claim to speak with authority on this forum, but to my very through knowledge at no time was the Western Rite ever prohibited. Rather, certain practices connected with the Western Rite, such as unleavened bread, were prohibited, but not after the schism, rather, at the Quinisext Council, which Rome never accepted. So you can make the case that the Quinisext Council is not an ecumenical council but a local one, since Rome, while still in communion with the Eastern churches, did reject it, and was not excommunicated. In fact it was the Romans who excommunicated the Patriarch of Constantinople; the anathemas came later. The fact that Antioch and ROCOR among other jurisdictions (Romania, for example) indicates that there are in fact no canonical impediments to the Western Rite.
And I think is uncharitable in the extreme to label the attachment Western Rite Orthodox have to their rite as being along the lines of "because we want to." When St. Tikhon of Moscow was alive there really wasn't a viable English language alternative to the Anglican liturgy, so modifying it to comply with Orthodox theology must have seemed very reasonable, especially in light of the close relations between the Anglicans and Orthodox that used to exist. Likewise, asking people to change their style of worship is a stumbling block; if the style is not heretical, there's no reason to make them change. And St. John Maximovitch confirmed that it was not heretical.
What is more, I think you're ignoring the huge liturgical diversity that exists in the Byzantine Rite. There are a vast range of musical styles, two extant Typika and several extinct ones, six Divine Liturgies that have in recent years been celebrated in a Eucharistic context, including St. John Chrysostom and St. Basil, but also St. James, St. Mark, St. Peter and that of St. Serapion, recently celebrated by Metropolitan Seraphim of Piraeus for the first time in more than a thousand years; that liturgy is found in what is probably the oldest complete service book in the Christian church, the Euchologion of St. Serapion of Thmuis, which includes a complete set of services without the additional canonical material you find in the Apostolic Constitutions, for example. There are also highly diverse ways of celebrating the liturgy. The services of the monks at New Skete I am confident look nothing like the services in a Romanian parish church.
Technically, the Divine Liturgies of Ss. Mark and James aren't even Byzantine Rite, but rather Byzantined versions of the liturgies of the Alexandrian and Jerusalem liturgies. And the liturgy of St. John Chrysostom is derived from the Antiochene Anaphora of the Twelve Apostles according to the authors of The Eucharistic Liturgies and several other textbooks in my posession.
So basically, the Byzantine Liturgy slowly evolved and drew from all of the ancient sees. And the old Roman liturgy was actually in many respects similiar, especially the Good Friday and Holy Saturday services. Up until 1955. And the Byzantine Rite probably gets its liturgical color scheme from the Roman Rite, since from what I've read the old Typikon only specifies light or dark vestments, and this is congruent with, for example,the Coptic Rite, which uses dark vestments in Holy Week. So I beg you to be tolerant of your brothers.