Sometimes things like ethical shopping can seem like a bit of a joke and I'm not advocating it as a major way to change the world.
What might be better would be to have an anticapitalist movmeent with direct action stunts against the major exploiters, as a way of raising consciousness about these sort of issues and then funding trade unionists from say Indoenesia or Bangladesh perhpas
And of course having powerful unions here.
But I wouldn't completely dismiss such concerens- I rember a couple of good demos/ one against Gap where people went in putting out leaflets about union busting etc 'what's outrageous sweatshop wages, what's disgusting union busting' and when management tried to throw us out the shop we said right they're trying to ban peaceful protests saying everybody out, we say everybody in.
Sure it's only symbolic action but it can be a good way of showing the power of organised resistance even if only to close a shop for half an hour and create a bit of disturbance- we were nice and polite, whilst being firm about not moving and most shoppers seemed sympathetic. And the workers mainly. Plus it was a bit of a laugh. and you can raise serious stuff like sending money to trade unionists organising in Indonesia etc and try to apply the lessons- if we can take over the shops through this sort of action even if only temporarily can't we take similar action in colleges, workplaces, offices in protests and union actions?