I think the tone of the setting is that it is supposed to be relatively ubiquitous. Heck, in a recent interview Lukas even described the genre of the universe as "Cyber Noir". I definitely think that is the case. Many runner IDs are likely not as interested in helping people as they are interested in either making money, getting bragging rights, or pure and simple revenge/vengeance.
Also not all of the corps are strictly evil... or rather not all of the corporate sub-divisions are strictly evil. I like to imagine that the new Jinteki ID previewed in H&P might actually operate in that grey area. Agendas like Medical Breakthrough let you get some insight into public perception, and think that maybe the corp is not always up to no good.
The game operates in a universe of grey areas. The board game and the novels convey that very well.