You don't need to be a beer snob to think that Canadian, Coors Light, Lucky Lager, or Molson Pilsner (the preferred brew of Saskatchewan Roughrider fans who wear the 12-pack cases as hats) is swill. All you have to do is try drinking any of them.
I've lived in Quebec, Ontario and BC during the time I've been a drinker and I've traveled in the US extensively too. So I've had occasion to drink all sorts of crappy macro brews through the years. When you're young, you're more focused on bang for your buck. You want to buy the cheapest beer so that you can buy the most of it for volume drinking. Once you get older you realize that it's better to pay a little more for a beer that actually tastes good rather than the cheap stuff because once you're older you are (hopefully) not drinking to get wasted and are looking for something that is pleasing to the pallet and pairs nicely with your food.
Crappy Beers I've Tasted Throughout the Years (partial list)
Molson Export
Molson Canadian
Molson Brador
Molson Pilsner
Labatt 50 (only still popular in Quebec, where ale outsells lagers and among Italian immigrants in Ontario)
Kokanee
Lucky Lager
Pacific Pilsner
Laker
Miller Genuine Draft
Miller Lite (or any light beer, for that matter)
Wildcat
O'Keefe Ale
O'Keefe Extra Old Stock (malt liquor)
Champlain Porter
Dow (OMG it's soooo awful)
And then if I think about the USA...
Matts
Utica Club
Old Milwaukee
Pabst Blue Ribbon
Red White & Blue
Keystone
Schmidt's
Blatz
Schlitz
Hamm's
Olympia
Rainier (originally brewed by Sicks Brewing, which should tell you all you need to know)