When Wolverine was first created in that Hulk comic his creator wanted to make him Canadian because he himself is Canadian.
Marvel gave him the OK but here's the thing, no one expected him to get so popular.
Once Wolverine was getting closer to becoming the face of the company Marvel attempted to retcon him into becoming American because they didn't want character who's not American being the face of their American company.
All of the attempts didn't work due to fans, both Canadian and American, being against it.
Being Canadian was a part of Wolverine and getting rid of that would take away something important from him.