Most Google employees, if asked a few years ago, would've told you they were confident Google would never participate in something as unethical as the American drone program. They were wrong.
Corporations do not have a moral code, they operate on profits. They are effectively psychopaths, and any time you associate a corporation with human traits like ethics or morals, you have misjudged it.
And bear in mind: Corporations are not a singular person. You could believe the guy responsible for packing the Google Toolbar in every other installer you downloaded off the Internet will never betray you, but eventually Sundar Pichai will be replaced by someone else, and corporate focus can, and will, change.