If its so clear, please point out what should clue in Auster to Steyn's irony.
Auster is apparently too thick to recognize it.
So according to you, Auster is not intelligent enough to see the emperor's new clothes.
I wouldn't know about that. But he's evidently not intelligent enough to recognize Steyn's irony -- at least in this particular case.
In no way is Steyn proposing that things be allowed to continue on their current course. Instead, he is engaged in convincing his readers that a.) there is an immigration problem and b.) if things are allowed to continue on their current course, the nature of Canada will change.
Before a solution can emerge, you must first convince the public that there is a problem. The most effective form of persuasion is to allow the reader to arrive at the desired conclusion on his own.
Auster is evidently not of this school.