Damn, that's a ruthless (and coward) father if true.
Your country should never be above your child's integrity.
Sacrificing her life was one thing. Letting her death be a spectacle, where everybody in the crowd was loudly demanding for her death and calling her a monster to her face, as she was facing her last moments, knowing that despite her innocence she will be forever remembered as a despised villain and spat on her grave, was way too much, especially since it was uncertain, risky plan, born of a chance (poison attempt by crazy fan), that didn't even guarantee much success later. In first chapter Constance mentions that the hall where she was condemned by prince and Cecilia was now famous place for couples, she already is part of a popular legend about triumph of good over evil.
She could be a great noble despite her flaws, something that her kingdom clearly lacks, and she was thrown to the wolves by her own father. Did he not realize that marrying her mother could come with political risks, and prepared to protect his kids? Or he could even decide to not have any, they seem to have some pregnancy-preventing stuff.
EDIT: I've just read on Reddit thread comment by AgentRobynBanks that that one great general, falsely accused (probably Faris doing), was
saved by Scarlet's execution as well. I guess they saw great general as less expendable than talented noblewoman.