And it's not exactly easy calmly explaining things to someone that's so mentally and emotionally damaged. Especially with the growing tension ever since she arrived.

Let's not forget, she's kind of right. Steven didn't want to bring her back and only did it to save the planet.

One thing I've seen people bring up though is that Bismuth, Peridot and Lapis could've chimed in and talk about how they also attacked Steven in the past, but are good friends now. It's kind of a problem with the movie as Spinel doesn't really interact with the others all that much, as it's mainly just Steven. Even Pearl could've talked to her, considering they knew each other and also has her own hangups regarding Pink.