Three points to make for me:
(1) Given that he was flying from Denver, they had to know that he was a kid. They would need his age and passport info for a trans-border flight.
(2) I didn't know the part about the policy that was quoted in the article. Here it is in full directly from the AC website:
Youths travelling alone (ages 12 to 17), for whom the parent or guardian has not requested the Unaccompanied Minor service, will be taken care of by our agents. We will also arrange for accommodations, meals and transportation if needed.
This is here:
https://www.aircanada.com/ca/en/aco/...ellations.html
They definitely didn't live up to that for this kid.
(3) In an earlier but similar case AC said that they couldn't book a hotel room for minors. If this is the case, then why does the policy on the website say that they will arrange accommodations for minors if needed?