The cotton and wool mills may not have been great for the Luddites, but everyone else benefitted. Using terms someone else used in a sibling thread, they were a "net benefit for humanity".
I don't think the parent is making the argument that this level of automation can't be a net benefit for humanity, just that if it results in nearly the entire middle class and down being laid off at the same time with no recompense, that's an almost perfect storm for revolution, violent or not.
As long as people working in a warehouse identify with the middle class, inequality will continue. There is very little class conscience in the US, from what I can see. They sooner identify as "poor" than as "working class".
The middle class is on the chopping block too. The lower class will honestly probably last longer than the median of the middle class, like paralegals, etc.
Standing in the same bread line creates an awful lot of solidarity.
Thinking "there will always be something else for everybody to do" because "there's always been something else for everybody to do" is like the dinosaurs thinking "we've always been fine after a meteor strike".
Some people might argue that wealth concentrated in the top 1% is a net benefit if you look at it as one big pool of resources. But will the remaining 99% actually see any of that benefit? Or will the 1% simply tighten their grip, keeping the rest dependent on their “generosity”?
"Rising tides lift all boats" — one of the problems with the mills, was that the people who got richer from them didn't help keep the impoverished Luddites from drowning. This is why Marx et al invented Communism. Can we, perhaps, avoid doing it all so badly this time?