I can tell you what we often hear as the primary reason, and then I can speculate about what might be going on.
We're often told that the reason for withholding this data, for not making it publicly accessible, not collecting it more widely, etc. is really to protect the privacy of Canadians, since there may be some issues particularly with a general release of the data that would compromise the safety and privacy of Canadians were those data able to identify particular Canadians. We have very little reason to believe that is enough of a concern to suppress really valuable information. Is it somehow, through de-identified data, still possible to identify particular Canadians? It almost never is. Maybe there is a slight outside possibility, the way there is with census data for that matter, but not enough for me to believe it's actually a legitimate reason for not collecting this data and not allowing it to be freely, publicly accessible to be analyzed by people like me, Dr. McKenzie and others in order to inform our country about what's happening to us.
That brings me to what I think might be going on. It's unfortunate, but I do think that when we don't collect data, that's at least one way in which we can ignore the evidence. We can equate our own opinions with a claim that those opinions are facts, because the facts simply aren't available to us.
My sense is, as you've pointed out and I've pointed out before, that with data and the ability for independent scientists to analyze that data comes a groundswell of evidence that in one way forces us to at least admit to the facts, to at least have to contend with and confront and recognize the fact that there are empirical evidence sources being put before us, rather than having a situation in which anyone can say virtually anything and we don't really have a good way to contend with or refute what people are saying.
I think that part of the hesitation may be that this actually creates some serious empirical demonstrations of what's happening in our society and that then, as Dr. McKenzie said, that's not the end; it's just the beginning, and that will make us have to move forward with action.