The popes most certainly does see them as Christians and even thought that the Fourth Crusade was a complete disaster.
HA! the pope thinking it was a disaster, if I recall correctly that train of thought only lasted until the treasure and holy relics looted from Constantinople started pouring in.
The entire dispute's pretty stupid as it's more about who should have control over the church as opposed to a difference in doctrine like Lutheranism vs Catholicism.
This might have been true at the beginning of the schism, but after almost 300 years there were definitely some doctrinal differences.