I can only guess that the Labor Party leadership was simply terrified that a terrorist attack might happen in Australia over the Christmas holidays.
It can happen anyway. With or without crypto-busting legislation.
While accepting Somali (and other) refugees more or less with no questions asked in the 70-es was right and moral, not mandating integration always gets you in the end.
It is the norm that in the absence of integration the second generation swerves widely to the right of Attila the Hun. Whatever the underlying reason, that is a well known fact.
People may cringe at what, for example, the Danish are doing, but as far long term social stability what they are doing is the right thing. We need more of that.