I don't see the problem. He was touching the stone like 1" past the line? That didn't look intentional. It's not enough to gain an advantage. There's no way Sweden could see that with the naked eye and be confident enough to call him out. Was Canada doing that every time?
If someone accuses you of cheating, that seems like an appropriate response.
I like the drama though.
EDIT: I stand corrected. Looks like it's illegal to touch the stone surface at any point. Can only touch the handle. I still don't know what kind of advantage he'd gain, but the stone touch looked intentional.