True, but the argument of saying that their only intention was to humiliate would be moot since they'd be an indirect cause of a wide range of potential outcomes including suicide.
That'd be like telling someone they should kill themselves, and when they finally do and you're asked about it saying "I never thought he'd actually do it".
After telling that girl a message that more or less suggested to take her own life, that goes beyond intent of humiliation. They are responsible in some way shape or form regardless of the medium used to do so.
It's just unfortunate the girl didn't wisely use the online features and was mentally unstable enough to be pushed over the edge over something so asinine and ridiculous.