But assuming it is for argument, then clearly what would be called "idealist liberal moralizing" has actually worked historically.

This is sophistry. What has worked is organizing around a moral cause, expressing one's own moral convictions, and inviting others to join them. This is fundamentally different behavior than telling people they are bad/immoral people who are supporting the suffering of others (i.e. demonizing them).

More so than first-world "I can do anything I want because I've labelled myself proletarian, it's every other class who's morally compromised."

False dichotomy / strawman that no one in this thread has actually put forth.

Which is why you people switch from "morality doesn't exist" to "it's immoral to make '1st world workers' (actually you) not eat slave chocolate."

Way to out yourself. No one proposed it was immoral to make 1st world workers not eat slave chocolate. In fact, that's the only thing that would work short of revolutionary liberation - organize a group of people with shared moral conviction and get a reform in place to structurally prevent access to these products, either through law or through "voluntary" capital allocation, both of which require interest convergence.

And you'll say, actually socialism is more effective at improving working conditions than boycotts, but it'll be based on a bad implication that boycotts hinder the advancement of socialism and can't be done at the same time.

You can stop othering me any time you want.