Contrary to what many people seem to believe, most Americans haven't been actually brainwashed by crappy mass media. Also, educational systems vary from state to state and even city to city. Most high school history programs don't even have time to get to Vietnam, let alone 9/11. College classes that cover it investigate it in a lot of depth. Though I'm not really sure what our educational system has to do with this. Most of us who watched those towers fall were adults. And we have families, and friends, and the internet, and the basic ability to use our brains to come to various conclusions about why it happened.

Further, monster movies have been metaphors for one thing or another since the existence of monster movies. That is what the good ones are for, and even the crappy ones generally take a stab at it. Akira itself, as far as I can tell, is an extended metaphor for certain things that really happened in history. Culturally appropriating it to twist it into a metaphor for a different thing, because Hollywood falsely thinks Americans are too stupid to understand what Akira is really about, is the problem. Well, one of the many problems.