When the self checkout machine refuses to scan my item. I am very likely to just steal it. Consider it a payment for my wasted time and doing the work that used to be handled by the cashier.
If you're wealthy, it feels a bit like a subsidy of other people's groceries. You do the work so everyone can have low prices (or at least prices that rise slower), but if you don't care about lower prices, it's an imposition.
Or at least all that would be true were it not for the fact that there are other options to pay money for time. At my grocery store, the fee for having them do the shopping and scanning for you and bring it out to your car is a whopping $3. I can have someone bring it all the way to the front door of my house for a $10 fee and a $5 tip.
It's a long way from required that I waste my time at the self-checkout.
These types of justifications seem bizarre to me. Do we steal fuel because attendants no longer pump fuel? Or rob banks due to ATMs? Do we steal software due to frameworks and automation tools?
If you just want to steal things, steal them. The high horse angle seems crazy to me though. I doubt you shopped at the national chain supermarket you probably shop with minimum wage workers in mind previously. But it's a good moral high ground to hold because you now steal as it's easier.
This logic is the part that confuses me. It's more convenient to steal a car when you're walking, or mug someone than work a shift at your job.
If I walk into a shop with an attendant and their point of sales system is down, I don't start taking whatever I want. Inconvenience doesn't justify crime.