This is also what a lot of other countries do so it's consistent with "the way things are done".
Finally, it seems politically expedient. There are already provisions for prioritizing Masters degrees. This change is a modification of those provisions. That (crucially) doesn't have to go anywhere near the legislature.
These particular masses are not huddled. Nor are they all leading lights (though some will grow into greatness in time) . So there are also plenty of reasonable arguments against this approach.