That's correct. But this is why you should shape your purchase habits in different ways than choosing lack of automation.
For instance, choose to shop at a coop grocer, where the workers are paid a livable wage and usually also become member-owners with voting rights and a share in the profits. (There are also consumer advantages to consumer coops, obviously.) In this case, it'd be to the workers' advantage to automate things which make sense to automate as they share in the higher profits and possibly a higher wage as well.
Personally, I don't use self-checkout usually because cashiers are almost always much faster when you have a lot of stuff. But generally, I'm much in favor of automation.