The only thing you can count on is people work towards serving their self interests, most of the time it's in a non-destructive manner, but it can also come at the expense of others. Sure, we do have free will as humans, and occasionally some of us do stuff that is truly altruistic but hat isn't the norm. Breaking this myth that they are helping us, more than they're helping themselves is tougher than breaking self destructive religious beliefs.
They work for your vote, along with the rest of the fickle crowd's vote. Profiting from, and manipulating our collective ignorance on a multitude of subjects the vast majority of voters are unqualified to judge for themselves.