The act of asking the same questions twice may seem silly. I agree with you that certain questions should not be included in the census because that information can be obtained in other ways, for example, from the income tax return.
However, I do not think that is the issue here. To come back to the compulsory nature of the form, I think the section on punishment by imprisonment in the Statistics Act should be changed, because it is clearly excessive.
You need to put that in perspective, though. The obligation being imposed on Canadians is not very demanding. It is not something that is impossible to do. It is relatively easy to do, and something we do for the public good. In my view, someone who complains about how long the form is will regret or perhaps experience, in two or five years, the effects of a lack of public policy targeting groups in his or her situation. So it is in the person's interest to fill out the form, even if he or she does not realize it.
Let us be real here. The person is not being asked to take part in forced labour in Siberia for six months, but to fill out a form that takes ten minutes to do.