Are those phrases not interchangeable in Canada?

Saying “# grade” might be more common where I am in the US, but no one would bat an eye if you said “grade #” because that is used commonly enough as well that people are used to it.

I don’t think it’s just a US thing. Even in places with more limited free speech, people can get away with saying ignorant and heinous things as long as it is technically within the letter of the law, or if the law is not strictly enforced.

It’s against the law in China to threaten violence or use hate speech, for example, but in practice, I think the law may as well be reworded to clarify that such language is only really illegal when aimed at Han Chinese people.

Not enough countries care about protecting anyone other than their primary in-group.

It is highly regional, too.

Despite the existence of the Department of Education (which Trump is trying to dismantle), there is no national standard for education in the US. In general, each state is free to decide upon its own policies and standards.

Some states, such as those in the northeast, have very high-performing school systems. So when that “1 in 5 are illiterate” statistic is mentioned (I actually have not verified that number, just quoting the prior claim as an example), it would be caused by low-performing states where the situation is much more dire dragging down the national average.

Here’s a general look at quality of education in the US by state, though recommend folks look up their own numbers because I haven’t validated the numbers pulled in the article I grabbed this from.

It’s not a perfect divide between red states and blue states (Florida appears good, California less so, as an example), but in general we see the lower performing states located mainly in the South where the Republicans have more support. Basically, a less educated populace is easier to manipulate.