@Paul Their response to that is "[being a contrarian is no more a sign of agency than being supportive]".
I think the movie could have been more clear. Lots of people seem to interpret it as her not understanding that the marriage to Irulan is purely political, and she's just jealous and throwing a tantrum. I think it's clear that she's smart and thoughtful, not impulsive.
Paul thinks going deeper into messianism and imperial intrigue is the only way to protect the Fremen and get revenge for his House, and she thinks that's bullshit and that the power has gone to his head.
They're both right, of course.