An important part of the leftoid mythology. And patently false, by the way. Osama channeled funds of his own along with donations from Muslim countries. He never received a dime of U.S. money, or weapons, or training. All U.S. support went to native Afghans, not foreign fighters.
He did not need it for sure. But he did not work in vacuum. From the time of Soviet invasion of Afghanistan to the Taleban/KLA/Chechnya before 9/11 you can find a lot of strange alliances.