Capital is not one monotonous block. If we want any hope of bringing it to it's knees, selectively targeting it's weakest points or most reactionary elements is a valid strategy. This goes beyond individual "ethical consumption", because it's a coordinated effort.

Honestly, you might as well be against strikes, because they only ever target individual corporations. Yes, a general strike would be better, but they still build workers power.

Taking part in efforts like that might even help people to develop some class consciousness.