People go through contortions to square the dissonance between their ideology and their actions. Ideology serves people, not the other way around. At best ideology is a hint at what people are like. There are always gross contradictions between what people believe and how people act.
Ideology does not arise from pure reason, it does not spring from the void. Ideology does not exist on its own, only in conjunction with power structures; ideology is completely subordinate to physical power. Ideology does not create power, it rationalizes it.