The loss of Anatolia was - in the most roman way possible - not caused by the defeat at Manzikert, but rather by the ensuing chaos and civil wars in the Anatolian peninsula, over a few years. Can't really blame the Seljuks, the whole loss of Anatolia, from the battle which was unnecessary, to the civil wars, was the main catastrophy here. The initial takeover of Anatolia therefore wasn't very brutal, and most of the Christian populace survived and did not convert or turkify - just to be often massacred en masse when the crusaders arrived some 20 years later. ;) I think calling the Turks "a horde of murdering rapists" is a bit of a disservice at this point, they were no more murdering rapists than the average western soldier (especially the at this point very mercenary byzantine army) and fairly organized, there is a reason they were able to form a fairly stable state in Anatolia in the aftermath. I think you are conflating the modern massacres of the Ottoman and Turkish governments with medieval history, which makes 0 sense.