Never stopped shopping at Ralph's during the strike and didn't support the union thing at all. "You're worth what you can get if you walk out that door." was told to me many years ago and I abide by it still. Harsh but true. Look at the union busting that's coming with the airlines. Do we stop flying and conducting business to protest reality. No.
I'm not boycotting the stores because I don't like the stores, I do it to show my disgust with the actions of the workers outside. Like you said, "You're worth what you can get if you walk out that door." If they let you walk, then you weren't worth what you thought.