People's judgments of other people's decisions often seem so fueled by narcissism. That's not how she would do it, so she calls it "stupid". Ironic, since she's the one missing the point, whether that point is that the other person's found a better solution, or more simply that they're comfortable doing it in their own personal way.
Implied is a form of imperialism. Other ways being "stupid", one's own way is by definition the only sensible one and must therefore be adopted universally.
The result is a peculiar viciousness, an ugly lack of respect for difference which borders on contempt.