She's just....'stupid'
Much like Bertia, she assumed that as long as she follow the 'scenario', the result she expected will happen, and ignore the reality of things.
Obviously this backfired when both the thing the heroine herself did and Bertia did were received differently.
The heroine doing whatever the scenario was expected made her come out to be rude/stupid.
Bertia 'villainous act' ends up increasing more followers because of her nature/luck.
Minor spoiler below:
For example, in order to criticize any mistakes her maids make with tea preparation, Bertia herself studied it.
So when she criticize their brewing, obviously she mentions why they did it wrong.
As a result, instead of the maids becoming afraid/hate her when she criticize them, they take it as a lesson, and were grateful to fix their own faults.