The 180 degree change in the thinking of these demons actually had a little do with Rabbit, the new Demon Monarch. And the reason was her being timid! After the demons from the western forests were trapped, Rabbit was rather happy at first, but she slowly became aware of the subsequent problem it brought. Although she had Great Immortal backing her up now and she need not be afraid that those big demons would escape the array formation and get even with her…
But the future remains uncertain, if Great Immortal were to leave in the future and they put all the blame onto her, what would she do? Even if her cultivation level had risen by then, she still wouldn't be able to beat them as a lone rabbit.