With her husband dead, her kids were her only means of remaining “in power”.
With that end in mind, she “loved” them.
She let Bran be thrown off the castle and then tried to finish him off, to protect her claim to the throne.
She fried the Sept after being told to go stand with the other riff raff, instead of by the boy king’s side, as was her usual place of status.
She is bloodless and loves/serves only herself.