The western lefty guilt complex is a totally natural reaction to realising that your quality of life is largely reliant on the exploitation, immiseration and deaths of vast swathes of the earth's human and non-human population. It's not healthy to focus on this too much, but it's understandable. The problem isn't feeling it, it's failing to translate it into action against that system -- most people deal with it either by wallowing or by setting up the types of personal moral calculuses OP mentions, including ones based on identity and ones based on consumption, the ultimate effects of which are self-exoneration but no real change.

That being said, I do think that a lot of reaction against the ethical consumer mindset goes too far in the opposite direction and becomes a blanket excuse for amorality. Yes, all capitalist businesses are basically egregious, but some are worse than others, and it is actually good to avoid buying stuff that was produced in a particularly monstrous manner if you can afford to do so. Nobody's perfect, but you still have a responsibility to be good.