Not just that. But why the fuck is the control software so weak? Why does it allow remotely bumping temperatures to near boiling without any checks? Which idiot designed this system? Why aren't they out of business? Same with the people who installed these systems. Why on earth didn't they think to secure it?
Very likely they shipped with an ADMIN/ADMIN username/password and nobody changed it. Because who would want to break in to a freezer, right? It's not like there's bitcoin in there.
We've been telling people for years that naive threat modeling was going to bite everybody one day. And finally, here we are.
Go offer your services to these companies and see their answer.
The big IT firms syphon off all the talent with compensation these fridge and supermarket companies can't match. You won't find much talent there. Who is brilliant with computers and would want to work there?
But look also at how underfunded the basic blocks of IT are, how open-source is left to fend for itself. It is the whole culture of modern IT to hack things together and not make them well-defined and reliable.