No, here territory is that of the people she rules, the rightful heirs of Lordaeron. Those that once lived there still do. They just have a new leader. Like it or not, Lordaeron was and always will be the birthright of the Forsaken people.
She only had no regard for Garrosh. Then again so did the other Horde leaders so she's no different in that case. And the only thing she disregarded was in using the blight. Garrosh said necromancy was unnatural but never forbade it.Yet she utilized monstrous technology and necromancy despite this very same "other Horde leader" being against it.
It is quite clear that she had no regard for whatever any other leader told her, as she openly defied Garrosh and utilized everything he told her not to. Saying she followed orders is not right.
The Forsaken followed other Horde leaders(Garrosh only, to be specific) untill she returned. As soon as she returned, all the monstrous and attrocious things happened.
As for other leaders, she does listen to them. Lor'themar told her not to raise Blood Elves during the Siege of Orgrimmar and she didn't because she respects him.
And speaking of unnatural, monstrous, and atrocious... Who are you to decide these things? What gave you moral authority?