They're imparting general information to the general public. You are absolutely on a tourist visa while you are there and they can (and do) deny entry and deport people. You do not have some kind of right to visit Canada just because you are American.
The "correct" modern terms are Global North and Global South. But 1st/2nd/3rd are taking on a new meaning of Highly Developed/Developing/Undeveloped. Cold War era political scientists are raging against it but it's much more easily understood than Global North and Global South which also extend the idea that Northern countries are superior. (The given reasoning is that Northern countries are better developed on average, but come on...)
You absolutely need a visa. Just because you don't personally have to apply does not mean you aren't on a visa. And Canada already has a blacklist at the border. Adding more names is super easy.
People already bitch about not being able to go to Canada because they got a DUI. This is will absolutely cause someone's vacation plans to be fucked up. But more importantly this should be a policy of the EU and Mexico too.
24 hour light is considered torture. Imprisoning someone without telling them why, how long, or what should happen next is also considered torture. They are literal torture techniques practiced in countries without human rights.
Then there's the stories of people needing medical attention after border patrol "interrogated" them.
The guy lives and committed his crime on the other side of the ocean in a context which does not exist in this country.
The word "tenement" has a negative connotation specifically because of the UK's treatment of the working poor. The Grenfell Tower was only 8 years ago. You guys might not have the health insurance issue we have but you certainly have the "Parasite class killing and causing suffering for monetary gain" problem that is the root cause of both issues.
I'll just be over here checking into an assisted living home. Don't mind me.