Honestly all can do this based upon where the colder air enters which in most cases is the top and back of the fridge. Be it when cost is not a factor cold spots can be reduced but there will always be cold spots. Being in the door means that it will be less likely to freeze and if freezing does occur, being in the door will be the first to thaw or warm.
If I had to guess, it’s because the back/top of the fridge is more prone to freezing.
This is it. The door is warmer than the back and the mayo will separate if frozen
Also easier/more convenient to locate.
Honestly all can do this based upon where the colder air enters which in most cases is the top and back of the fridge. Be it when cost is not a factor cold spots can be reduced but there will always be cold spots. Being in the door means that it will be less likely to freeze and if freezing does occur, being in the door will be the first to thaw or warm.