There's a lot of this going around in the thread. Many of you are assuming just because you participate in the market means that you are a hypocrite for supporting another arrangement of economic organization. This is not really the case. We have no choice but to participate in the (capitalist) market, as it is the only place where I can receive the necessities of life. Obviously every purchase in the market is going to be reinforcing the capitalist system and all of its pitfalls, but there's not really much choice.
But yes, it's true shoplifting isn't an effective method against capitalism. It doesn't do anything to agitate workers against the ruling capitalist class, it only makes them resentful against communists (or otherwise) who claim to be shoplifting in order to 'smash the system' but are really just harming the workers involved. The Koch brothers aren't going to be taking the brunt of the financial loss here, it'll be the workers getting their wages slashed for a few weeks. Only collective action from the working class is capable of overthrowing capitalism and instating a new economic ideology. Individual action is useful when its being put towards this goal of creating that collective current of action, like giving an impromptu speech in a park that piques peoples' interest in the ideas of communism that they may investigate and learn from, but it's not so useful if it's going to be hurting the workers, which is the last thing communism seeks to do.