Plenty of revolutions have happened, before, during, and after the Cold War without U.S. support, the U.S. actively opposed the breakup of the Soviet Union for example, and yet it happened, and several democracies were created from it’s downfall, with little influence from the U.S.
dictators without the U.S. funding them FTFY
Even if the U.S. government did regularly fund protests/resistance against dictatorships, why would that be a bad thing? As long as it’s not singlehandedly deciding on regime change like in Iraq, I don’t see anything morally wrong with supporting pro-democracy causes within dictatorships.