British tourist detained by US authorities for 10 days over visa issue

The story is missing an important detail, I'm not assuming malice btw, why was she refused entry into Canada as well?

Edit: Lol, there's literally nothing wrong with this observation. HN has truly gone down the gutter. I know not everybody here is part of the hivemind but the few that are completely spoil the experience for everybody else.

She was not detained by Canada's border service.

Canada's border service sent her back to the US. At that point, the US can't exactly tell her to go back to Canada, and have her walk back and forth until the problem solves itself.

Immigration detention pending a return to the country of origin seems reasonable at that point. 10 days of detention to figure out transportation to the country of origin doesn't seem reasonable though.