We constantly hear about phones that die before reaching 0%, or losing the last 20% very fast. Google Nexus 6P comes to mind.
I'm fairly confident that what apple did was the most logical thing. They should have been more informative about it, but it's better than a phone dying at 20%.
Filed in the US (a heavily litigious society) against what was recently the worlds largest company (so right or wrong if they lose they can definitely pay)? I'm shocked that they found only 60 groups who could be both cynical and litigious :P Put yourself in their shoes.
I'm fairly confident that what apple did was the most logical thing. They should have been more informative about it, but it's better than a phone dying at 20%.