Yeah I know what you mean. It's OK if the government sets the privacy level like that.I think it has to do with preventing identity fraud / thief and expected level of personal privacy, mainly rules of consent. Government doesn't want to get caught in liabilities by giving information out without the person's consent.
But then, on the other hand, it seems wrong to me to require and applicant for no matter what government action (in this case, provide proof of canadian citizenship) to produce a document that they are legally not entitled to obtain.
Technically, unless you go through a crazy case at the courts, if you are not on good terms with your parents (so that you can get their certificate) but are a Canadian citizen by descent, it is impossible for you to get your Canadian Citizenship certificate. This might leave you not actually stateless (because you are technically a Canadian Citizen) but at least factually stateless (because there is no way for you to prove it).