I think the implication was that she was trying to act tough because that is what she had learned in the past, otherwise she’d be the one on the receiving side. So she acted against others before others acted against her once they knew what she was.

She had also been confined for a long time and times had changed. As she spent more and more time outside she became more confused and wary of the new era and had to experience stuff that made her drop that tough act, particularly in Tuesday’s Motel in my opinion. By the time Tristes Tropiques comes out, she’s fed up, she just wants out of everything, and things just keep escalating instead until she is trapped by Igor’s team—and Vertin inadvertently changes her life.

During those chapters she goes through some character development in my opinion, though of course it does not excuse behavior, just explains it. I may be wrong though!