Where's the line between technology advancing forward and weeping for buggy whip makers?
Self-checkouts allow several people to check out a few items at once, leaving the cashiers to deal with those with full carts. They are not inherently evil. It's a good technology (when implemented well with functioning machines...)
I'm all for treating employees with fairness and dignity. But expecting employers to not innovate in a competitive marketplace for the sake of keeping employees doing low-skill work makes no sense.
So... where's the line? Do we demand no automation in order to protect these workers? Or do we demand additional safety nets for these workers and the opportunity for them to improve their skills if they so choose?
One is that we can't keep people stuck doing the same thing as we need to improve productivity for people to see salaries going up.
In the short run, that usually means a given person is taking on more responsibility. So a person starts out as a clerk and is completing X transactions each day, and their wages come out of that value they add. As they become more senior, they take on more advanced roles like management that enable others to complete their jobs, thus adding more value and resulting in higher wages.
But not everyone can go the management route, whereas automation is a way far more people can get higher wages. If that one person can monitor several self-checkout machines, that person is completing several times as many transactions an individual cashier could. That's more value that person is able to add to the business, and thus higher wages for what is largely unskilled labor.
So the second line is whether people who are immediately displaced by automation are able to find jobs elsewhere. And that's a big unknown. So far we've seen automation expand overall economic opportunity, but Past Results Are Not A Guarantee Of Future Performance.