Boroda, I knew what you were doing; I was actually hoping you'd recognize my response. I guess I wasn't extreme enough.

The Fourth Crusade: It's a common belief that Pope Innocent III orchestrated the sack of Constantinople. That's just not true, period. The Crusade got deviated to Constantinople for a variety of reasons, which I'd be happy to go into if you'd care to hear it. The pope repeatedly warned the Crusaders not to go to Constantinople. In the end, when he was presented with the fait accompli of the fourth crusade and the union of the churches, he did accept it.
Sure, the division between the Catholic and Orthodox churches occurred in 1054, and was largely concerned with fights over the interpolation of the word filioque in the Niceo-Constantinapolitan creed. We can talk about the procession of the Holy Spirit, whether its heretical to use unleavened bread in the Eucharist, and the rest of the nonsense. But don't forget the attempts at church union at the Councils of Lyon and Florence.
Ah, yes, Alexander Nevsky and the Teutonic Knights. A fine Eisenstein movie, btw.
The notion of Crusade was born late and slapped on to all kinds of things. My personal favorite is the Children's Crusade, which is probably more myth than truth, but makes a damn fine story.
Yes, you shouldn't forget the Arian Christians, the Copts and the Maronites either.
The Catholic/Orthodox slam is that while, theologically the Catholic church developed a notion of being the universal Christian church (and thus offensive to anybody in the East, who considered themselves both Christian and "Not those guys"), and tried to integrate the other groups (such as the Armenians, MAronites, Nestorians, Jacobites and Greeks) into the one, universal church (not gonna work guys), the theological response of their adversaries was one of defining things along ethnic lines.
Politically, of course, things were different. But theologically, it worked this way (note: I'm looking specifically at the Greek Church): Here comes a bunch of well meaning but ignorant Dominicans and Franciscans to the East, to try to make the Christian population realize they're part of one universal, pan-cultural church, just with different rites. Of course, there are a few small things they have to agree with, such as the nature of the Trinity (!).
There are two reactions:
A. You guys are full of crap. There's no way you can prove those arguments the way you do. Aristotelian logic cannot be used in matters of faith; here's what we honestly believe.
B. Not only are those guys full of crap, so is A. A. shouldn't use logic in discussing faith.
A. B. is a moron, plus what some of his buddies are saying is, frankly, heretical.
B. A. is an amazinhunk, plus he's a foreigner. Remember the Fourth Crusade? Do you want those foreign bastards running your religion?
B. wins, and ethnicity becomes a mainstream current in (Greek) Orthodox theology. A. says, "Screw this" becomes a Catholic and lives out a comfortable life without renouncing his "Greek Heresies".
So the palamite/hesychastic theological foundation for the church wins out, and the place of ethnicity in orthodoxy is reinforced.
Meanwhile, in the West, there's the reformation, and the council of trent. Then the RCC becomes really nutty too.
In all fairness, there are other trends in modern orthodox theology, some of which are coming to the surface now. But tradition is hard to break, and even today, you can't publish balanced treatments of dude A. in certain parts of the world without people thinking you're slamming their church. However great a thinker and mystic Palamas was, his arguments in the fight with Barlaam, a fight that shaped the modern Orthodox religion, need to be inspired by God to be considered superior to his adversary.
Anyawy, I'm sure there are strong biological drives against people of differnet ethnicities; it's an ugly part of human behaviour, and one that manifests itself continuously throughout human history.
Finally, I recognize that, for a host of cultural and political reasons, the Russian Orthodox Church is not as powerful or pervasive in Russia as the Greek Orthodox church is down South.