Support is not the same as toleration, indifference, or complacency. That being said, they are choices, as you say, though awareness and fear do affect culpability (something that seems to be implied in your comment).
For a system you are outside of, sure. But we're talking about a system that people are actively participating in. E.g., the people who spend 50 hours a week working at Uber are supporting Uber, whatever their attitude toward it. I suppose the possible exception is somebody who goes in and consciously sabotages the place for 50 hours a week, but that's the edgiest of edge cases.
