When no one owns a piece of property (or in this case a geographic region) and barring any respect of homesteading, it is difficult to hold individuals and firms accountable for whatever takes place there, as noted by NewScientist: “Critical space junk threshold approaching.”
Or perhaps a more fitting alternative headline could be: “Do as we say, not as we do: It is okay for the State to litter however you still cannot”
See also the Moon Treaty and the Outer Space Treaty.