First, 400 pounds is a pretty beefy fridge, most basic units are a lot lighter. 400 pounds is coincidentally the top end of the average weight search AI gave me too, the lower end being 200 pounds. I've moved a few fridges over the decades, they'd have been hard pressed to get a 400 pounder wedged in there like that.

Second, a fridge is mostly empty space. The weight is certainly not distributed throughout. If they put the heavy end (usually where the compressor is) hanging out the back, they probably wouldn't have made it very far anyway before the thing ejected itself. They are primarily difficult to move because they are bulky and lack safe handholds for lifting.

Third, police modifications adding weight would necessarily require modifications improving the suspension. It would be pretty bad design if putting three 200+ adults in the rear of a police wagon were enough to make the vehicle unsafe.

This is all a pretty dumb thing to argue about. After all, I agree that the cop in this case was an idiot. That's mostly because storing a fridge on its side is a dumb move, but also because I do actually believe that storing it as we see in the photo would be bad for the car too. Fridges have lots of sharp edges, plenty of opportunity to destroy the interior, shatter a window, or cause an accident. I just don't think weight or its distribution is the problem.