They also didn't mention France which got a lot of Quebecois worked up apparently, which is why the person who made it modified it to have "lily," a French symbol, in "Thistle, shamrock, rose entwine" → "Lily, thistle, shamrock, rose \ The maple leaf forever."
I personally like "The Maple Leaf Forever" way more because it's epic. I don't know why, I just don't like "O Canada." It's really ear-grating if not sung by the proper person/choir (no offence). For example, this rendition is quite "ear-grating" in my opinion:
It just has a major cringe factor.
I've also memorized the entire lyrics of "The Maple Leaf Forever," so that helps.