You are correct that it wasn't written that way. I learned it as "O Canada, glorious and free" as a child and was surprised when others sang it later as "God keep our land, glorious and free". This is similar to the U.S. Pledge of Allegiance that was fine until 1954 when they had to jam the contentious "under God" into it.

I wonder how those who gloat about how the poor widdle atheists are offended boo hoo hoo would react if it was changed to "there is no God to keep our land, glorious and free" or similarly the U.S. pledge had "under no God" added. This is basically how we feel about this change. Just leave the religious references out and one's beliefs or lack thereof to our own consciences.