I was born before 2001; I read the letter in question back in 2002. The details are different, but tenor of the reaction was the same back then: misrepresentation of the content, the hyperventilation, and twisting it to fit political agendas.
Really, this is young people doing exactly what they should do: Ignore the propaganda. Go back to the primary sources, examine them, and engage in critical thinking. Osama bin Laden was correct in his diagnosis of many issues. Trying to hide it from the younger generation, and browbeating them when they see the huge cracks and glaring contradictions in the story won’t work forever.
A big component of this is the cold war with China. Western corporate media have been primed by their governments and by capitalists for years now to put anything even tangentially related to China in as bad a light as possible. People in the media do it reflexively now. Remember the weather balloons earlier this year? People still think they were spy rigs, even though no such evidence ever came to light. Our media are complicit with our government in their warmongering.