A thing about religious (and other) people and the illusion of free will

[Ahriman]

This doesn't follow. Nobody is forcing people to worship these entities/people/deities. Not unless you want to imagine these entities/people/deities are not only real but also have special powers that allow them to influence or control people's behavior against their will.

It's almost like you haven't heard of brainwashing.

Brainwashing can't make a person do something he or she wouldn't be willing to do in the first place. Brainwashing could encourage specific behavior, but it won't be enough to change who a person is, on a more fundamental level.