I don't think it is unusual at all to be honest; the one this fridge replaced was also white, and the neither seems to have a back that is intended to be looked

I don't think it is unusual at all to be honest; the one this fridge replaced was also white, and the neither seems to have a back that is intended to be looked at - there are plenty exposed seams, plumbing, the compressor. Offhand, it doesn't seem like there would be much thermodynamic advantage in the heated surfaces of a fridge being black. If there were, wouldn't you expect that car radiators and such would be black anodised too? I'd imagine conduction is going to be a much much bigger effect than radiation - other concerns like cost, durability, thermal conductivity of the paint, and aesthetics will likely be more important in deciding what colour paint to use.