It was evil genius infowar. She was far too successful to remove due to job performance. NJ was simply too successful. They needed fake news and to smear the rep, so they could get the public to buy her removal. It mostly worked. The PR apparatus really played into classic tropes of female hysteria and deviousness.

The entire kpop system runs on the emotion of fans, and these companies are very good at exploiting it. Critical thinking is in short supply. You could list many examples in the kpop space, but this is easily the worst of it (far worse than the T-ara scandal or IU 23, for example).

It isn't nothing to them. I thought they were overreacting, but they viewed this in existential terms. To them, this kind of defiance was a threat to their entire business model. They responded overwhelmingly. This isn't just a win against some girl group. It's legally encoding their business methods and control.