Yes, she showed that she had very little loyalty to the band, or common sense. Remember the bit where she "accidentally" gave the key to Bono's room to a couple of people she barely knew? And the time she and Mullen were confronted by some thugs and she stupidly gave them the finger, creating a really dangerous situation. The fact that she would mention these incidents in her own book showed what an idiot she was. Also, there were many factual errors, like her claiming that Bono met Bruce Springsteen for the first time in 1987 (they met years earlier), and saying that Bono wore women's (!) high heels at this "first" meeting so he would appear taller. I guess his usual high heeled boots just wouldn't do the trick.
Yeah, that book was surely one very stinky pile o' crap.
Bono says this lawsuit is not about the book, but you can't help but feel that's surely part of it. And who can blame him?