Did you even bother to read the links?
If you stay 31 days the form is required. Failure to comply may mean they can refuse you entry on your next trip.
It is true we don't require a visa for visits under 90 days. But if you stay 120 days an extension needs to be applied for.
The border folks on both sides have a great deal of power, and discretion. Some times you may run into a "tin pot God" on either side. I think there may be a lot more TPG on the USA side no
Maybe go back and visit the border services sites or even the Canadian snowbirds site before quoting or posting a random internet article. You are definitely incorrect. You will also note under the visa waiver program and enter the link in your link you provided, you will see Canada is not on the list