Seems pretty brutal to me though.
They let me in, but had me sign something that I would leave within 30 days.
It also means that if you came here fleeing persecution that you might not be able to return.
As far as Canadian law goes, there are two factors at play in the parent's events;
* NAFTA work permits are applied for at the border, on entry; they operate differently from the 'normal' work permit streams.
* Permanent residence is conferred at the border, but the application process can happen either inside or outside the country depending on the stream. There are also limited 'inland' options which evidently have expanded (https://www.canada.ca/en/immigration-refugees-citizenship/se...) in recent years.
In neither case does Canada have a blanket rule that an applicant must leave the country during the whole of an extended application process, and even 'abroad' processes can often be carried out while an applicant is living in the country on other status. (It can get awkward if a consular interview is required, though.)
Unlike the US, Canada is generally comfortable with 'dual intent', where intent to apply for permanent residence through legal channels is not disqualifying for other sorts of statuses.
It is actually really bizarre that the USCIS would essentially take the applicant's word without any vetting before this memo.
It’s just how things are done.