Why this change you ask -- well here is the explanation given by the Globe and Mail and a spokesman for the government:
The move is a response to protests from some Canadians who resented the personal questions in the long form. Similar opposition has been raised in the United States by some Republicans opposed to Washington collecting and analyzing data.
“Our feeling was that the change was to make a reasonable limit on what most Canadians felt was an intrusion into their personal privacy in terms of answering the longer form,” Erik Waddell, spokesman for Industry Minister Tony Clement, said Tuesday.
Given that this information is locked away in the bowels of the archives and annonymously aggregated for analysis it is hard to see what the real priovacy concern is here. Furthermore, sometimes minimal intrusions into privacy should give way to the idea that decisions should be based on knowledge and understanding rather than ignorance and prejudice. Of course, this government has largely been dedicated to the idea of decision making on a data-free basis (see management of the prisons and crime file for this purpose) so why should anyone be surprised?