Would you be much happier if it was a normal room, but locked from the outside?
I never saw anyone talking about "cages" until about a year or so ago. It seems the alternative of better accommodation isn't what people are demanding here, but rather, giving children a waiver to break any and all laws. If you want to see children being forced or recruited into cartels in record numbers, making them immune from any kind of border enforcement is a surefire way to do it!