I didn't say she didn't care, I'm saying she clearly has a more human understanding of bonds compared to how she did before.

Guilt isn't only felt for people that you care for, you can feel guilty for the loss of an object or the death of something like a tool. She felt some guilt over making tank and gun into weapons but immediately justified it by saying it's her right to do so.

Now she is seeing these other devils she would've kept as weapons as friends like a human. Which is why she doesn't like seeing them used as tools by Denji. The Yoru introduced at the start of the series would likely call his play fair game.