> The fraction of the total waste stream that you can affect is irrelevant when deciding whether to recycle. Any single industrial waste creator could make the same argument-- my company only creates 0.001% of the waste stream, so it doesn't matter what I do. This has to be wrong, because we know that the total outcome is nothing other than the aggregated behaviors of all of us, and the total outcome matters.

It's not wrong. There are two different answers: what's best for the individual and what's best for society/collective/etc are not the same thing. This is why legislation and reduction of barriers (like single stream recycling) are necessary.