The whole point of the warrant was that the government suspected Uber of hiding evidence. Allowing them to pick and choose the data they unlocked from the servers would be counter-productive.
In Canada, like in the US, warrants have to be specific about what exactly the police are looking for. If the warrant really was "give us all your data so we can see if you're hiding something", that's not legally okay, and I can't blame them for trying to prevent the disclosure.