There are two factors to consider though.
On the one hand, you're correct that it does nothing for the American worker to bring manufacturing back if it means huge buildings with skeleton crews and machines that effectively run themselves. I don't particularly have a solution for this. Americans have gotten used to the price of goods being artificially low because of inexpensive labor in impoverished countries. Unless we want to take a manufacturing approach akin to Germany or the Nordic countries, focusing on high quality precision built or luxury items, we simply can't produce goods at commodity prices while both paying people enough to live well on and producing the kind of profit that is required by investors. So that's where YC sees machines as solving that conflict, at no benefit to working people.
That said, there is the advantage that we have seen how fragile the global JIT supply chain is to disruptions. Either political, environmental or just plain Acts of God like COVID. Having goods produced much closer to where they're consumed is something I think every country needs to invest in. Especially for goods that aren't just nice-to-haves but necessary for basic functioning of society. Things like construction and repair materials, medicines, medical devices, etc. I support building up a greater local resilience over global dependence, especially what with climate change on the horizon.
I wish we could do this in a way that meant good blue collar jobs with strong benefits and union wages. But you can't ever expect a investors YC to take that path.