I don’t think the “US is perfect” curriculum has been taught in over 30 years. We read Howard Zinn’s a People’s History over 20 years ago in my high school.
This is another ethos appeal as they name Howard Zinn, a well known figure, but it's also a pathetic appeal as they're just relying on the audience agreeing with them presumably through the emotional appeal of disbelief/exasperation because they learned it over 20 years ago so surely it is in place everywhere by now is what they're implying.