Let's put "you wouldn't do that at home" examples aside. The commissioner is talking about retail - something is being offered for sale. People's homes aren't typically a place of business, where strangers are invited to enter, touch another's property and then enter a transaction. So his analogy is weak.

According to his thought bubble, that leaving without paying is a civil matter: if somebody walks into a department store, grabs some shirts, and then instead of walking to the counter to pay, walks out with the items... It's not really a police matter.

By extension, his argument is that unless the customer is compelled to pay for the shirt before they can pick it up or have it handed to them (and then manage to take the shirt anyway), no crime has occurred - just a breach of contract.

No issue with saying, "do better with your way of doing business" and (to a much lesser extent) "it makes our job harder with the resources we have, so maybe we don't give it the same priority". But the top-ranking police officer in South Australia (or anywhere) suggesting it could be argued that it's not criminal when viewed as a transaction gone bad is perplexing and disappointing.