[no need to excuse that language, because it's exactly what she feels. She can excuse Ezra this time.]

That was the message they wound up sending.

[because Alderaan's destruction was seen as an unforgivable offense, which it was, and many defected to or joined up with the Rebellion after all that. They couldn't pin the destruction on the Rebels, as much as they tried.]

But it was intended to instill fear and obedience into the galaxy. To show the dangers of rebellion.