I know this is a hard concept for you but when judging a character try and include things such as their mannerisms, tone and I don’t know.. overall experiences?
You’re viewing things as black and white, try and view them from Frost’s perspective. She isn’t just an aggressive meta, she has fears and emotions, lacks education and guidance.. so on.
She still did criminal things. And Joe as a cop should also see that her changing sides doesn’t matter to the law so if he thinks that he can convince Kramer to back down because she’s changed, he’s an idiot. So unless she gets a pardon, she’s screwed.