Yes, I agree, it had much more to do with economics than with religion. The religious identities just were a convenient asset in exacerbating the divisions between people...for those who wanted to do that. This has been a favored technique of fomenting wars for a long, long time...while the wars were in fact generally really about control of land, money, and resources.

I have had an interesting time playing computer games of the Roman wars lately. Those wars are always about the same essential things:

land
money
resources

Land and resources are a relatively slow, but very reliable and long term source of money and power. You have to have powerful armies to hold them. Siezing and plundering neighbouring lands is the fast way of raising a lot more money, which enables you to build a bigger army so you can prevent others from doing the same thing to you later.

It's totally ruthless pragmatism, masquerading as a desire to spread "culture" and spiritual truth and raise other people out of the morass of their ignorance and false beliefs. (ha! ha!)

No population is ever very appreciative of such outside cultural assistance. ;-) Consider the Iraqis, for instance.