I have voted for politicians that I knew were adversarial to my line of work (limiting expansion of the scope of practice) because I believed them to be a superior candidate for the rest of my values. When I properly educate myself, I can usually see the greater good in forgoing a small gain in the near term.
Unfortunately, having a little money makes many people willing to do almost anything to get more. Power and notoriety/fame is just as addictive to a lot of people. Some people believe that, if another person or group has success, that success has been taken from them and has to be stopped.