Boycotting only works effectively in a free society. If someone taxes your by force, and hands some of that money to these companies, then short of becoming an elected member of government, you can't do anything about it.
That's still not actually doing something about it.
IMO voting is the same as praying. I mean, sure; Your ruler may decide to grant one or more of your wishes, but you'll never know if it was them, or simply chance.
Also, my point was regarding boycotting, and how free association and volunteerism become ineffective when dealing with government or government sponsored corporations. Boycotting on free market ideals, means they don't make money if most people don't like them. This can't happen when the operation itself if funded through tax dollars and currency controls.