Sure, but how long would that take?
Centuries.
That's no good for the self promoting grifters! The problem needs to be solved this second, or everyone you love is dead.
The idea that you could easily foil this plan by providing better education and integration is actively suppressed.
No, I think it's really only about a feeling of lack of control in the face of very long-term demographic changes that make people want to do something, anything, to feel like an Agent, not a subject, of what is happening.
The ideology is very much a buffet that is used or discarded as seems useful at the moment.