alt Hacker NewsIt's absolutely oversimplified, someone from a small coastal town in Newfoundland does not sound at all like a person from much of the same area labeled "atlantic canadian" in Nova Scotia, or in larger cities like Fredericton or Moncton in NB. Putting basically all of NB, NS and NF as one large pink blob on the map is a drastic oversimplifiaction.
It also seems that whoever created this kind of gave up when figuring out Canadian speech patterns spanning longitude from east to west. Somebody from Kenora or Dryden or Timmins Ontario does not speak like a person from North Vancouver, BC. Vancouver region English is much closer to general west coast as it's spoken in a big city in WA, OR or California.
I'm from Ontario and its very simplified in my experience as well. Maybe the problem is the sample audio clips they have are all 'posh', its not how most people speak. Two large examples I can think of that even have their own wikipedia pages are the Ottawa Valley Twang (https://en.wikipedia.org/wiki/Ottawa_Valley_English) and the 'Torontomans' (https://en.wikipedia.org/wiki/Toronto_slang). I grew up in Toronto, and the latter isn't just something funny you see on tiktok, people actually talk that way.