From the way you described of the rust that had worked from the inside of the fridge doors, it showed that rust was probably contributed from your own liquid material that was spilled and seeped to the side of the inside of the door .
The rust could have been for some time already if the acidic spillage of liquid, like soft drinks and other food materials, was not cleaned up.
The corrosion starts from the inside surface of the door material. It further corrodes to the outside of the surface .
This rusting is not sudden thing. It creeps over time. The corrosion probably had gone on for several months, or even soon after you purchased the fridge.
Also, the water from the washing of kitchen floors may have contributed to the rust. The use of strong floor cleaner like the use of clorox, will cause rust. The clorox liquid is corrosive as it is a stain cleaning liquid. It probably have caused rusting on the doors, too.
During the washing of floors with mixture of water and clorox, the splashes of the mixture may have had wetted the door material from the underside of the doors.
Seriously, the material of the door is not made of stainless steel or steel that does not corrode. The material is normally a electro-galvanised coating on the base material of mild steel material.
The elctro-galvanised coating is a zinc coating on the surface of the base material. It helps to prevent rust but it does prevent rusting.
So the problem lies with 2 problems.
One is on the problme of the manufuacturer, Samsung. It did not have enough of zinc coating thickness on the metal base material.
Secondly, it did not have goos quality tests such as rust accelerations tests to see if how long will the base material last after the spillages of food ingredients, and floor chemicals, on is metal surface.
In any case, it is their standards of manufacture that consumsers cannot complain.
At best consumers should not buy their products. Consumers should continue to complain in "complainboard" in order force manufacturer to improve its quality standards to consumer demands.
Finally, the other thing is your maintenance of the fridge doors. You should also check if there is any punctuals in the internal surface of the fridge.
The pucture can cause liquid to seep to the base metal material. As the liquid in the base material cannot be cleaned, it can cause rust to occur from the inside to the outside of the metal.