I mean she saw him massacre her whole clan so can you blame her??
I understand your perspective, and I agree with it to some extent. However I do acknowledge that she has shown some growth in understanding the suffering that the Tantai Jin has endured in the past, and that she believes that she can prevent him from becoming the devil god if she makes an effort. Despite this, as Tantai Jin continues to consume more demons and become increasingly more “evil”, he gets closer and closer to the devil god that caused destruction in the future. It would seem inconsistent with her character to simply accept this and sympathize with him in every way.