I agree the average tech worker is woefully unaware of how tech illiterate the non-tech user is, but I would push back on the notion that basic security measures would've threatened the margins of a grocery store, and I am well aware of how they operate on single digit margins.

Tailscale pro pricing is $18 per user per month. Assuming you had one tech per store even, and 500 stores, that is a $9000 per month expense. Ok, not as bad as refrigerant and electric bill costs, but not great. So let's say instead of having a dedicated IT tech per store, we have 5 techs who work from HQ managing the infra for 500 stores.

$90. $90 per-month is all it would've taken to take these fridges off the public internet. If your margins are so razor thin that a monthly $90 bill would threaten profits, I question whether your business is even viable.