The Canadian government can tell the world how useful he was to the intel community and how his contributions were essential in killing hundreds of jihadis and preventing scores of attack on Allied forces.
They can then go one to say how much they are looking forward to working with him as a free man in Trendy Toronto, much more convenient than Gitmo, and expect he will help them mop up sleeper cells in Canada.
Then drop him off in front of the most malignant mosque in Canada...
There was no government to government pressure for his release. The Americans could have kept him forever.
Look to your own government, they are releasing terrorists all the time. Don't blame Canada.