Yes. The atrocities were, in fact, committed for the purpose of advancing the economic and political interests of the atrocity-committers (it could be argued that the Crusades were the exception, but I’m not entirely convinced; a region of the world, physical control over which is the point of contention for just about all of human history, probably has some intrinsic strategic and economic value over and above the mystical).
Yes. Religious manipulation was used to enlist the shock troops to commit the atrocities (Joe Footsoldier was probably likely to be more responsive to “these savages are the children of Satan, and must be purged by the sanctified fire and the holy sword,” than by “the king really wants the gold these folks are sitting on.” – not that Joe Footsoldier wasn’t going to keep an eye peeled for any baubles he himself might stumble across). But the position of what I regard as the true Christians around here has always been (as I see it), that these things represented abuses of the basic message of Christianity.
And that’s the point. Christianity doesn’t have “positions” and “arguments.” It has messages. Usually messages about love, and people recognizing the value inherent in each other. People, including some very misguided people who are really more concerned with their own place in life than with love for others, have “positions” and “arguments.” And some of them take the name of “Christian” to themselves, without even attempting to understand the messages. Some of the people who do this become very successful at manipulating others into assisting them with furthering their own economic and political ends. The tragedy is that so many people who are truly of good will let them get away with it.