I was born in the late '80s.. Did not know Palestinian terrorists killed an Israeli Olympic team in 1972.
It doesn't matter what you don't know. What's important is what you learn.
FWIW the Weather Underground was about burning draft cards. They had nothing to do with the Munich Olympics, The Irish Republican Army, the Palestianian Liberation Orginization (PLO), Patty Hearst, or the (SLA) Symbionese Liberation Army.
Unfortunately in previous times as in recient times vague links such the airplanes crashing into the world trade center buildings are mistakenly linked to Iraq (Almost all of the hijackers were Saudis) to weapons of mass distruction (none were found) to Sadam's Iraq that had no connection with Al-Queda
Breaking a couple of links seems all that's required for the masses to stand behind and tug against a chain with no enemy. Swatting a couple of hornets nests is sure to get insects swarming.
Why don't parent's teach their children about history?