When I was young, a mantra among progressives was that America had to stop operating as global policeman. Vietnam was the signal episode of arrogant and ultimately self-defeating American overreach. But there were plenty of other cases of the U.S. government doing the bidding of oil companies and banana barons, and blithely overthrowing left-democratic governments as well as outright communists (or driving nationalist reformers into the arms of communists.)
Though I surely did not become more conservative with age or my first paycheck, I found a few things that I do not want my tax dollars funding. Unless we stand up for our values and make an attempt to have some say in where our tax dollars are going, we are complicit in the very types of oppression to which we are ideologically opposed.