First off, Hitler was not democratically elected to be dictator for life. While the system could be manipulated (such as via the burning of the Reichstag) to make him chancellor for a term, it required force, not democracy, to keep him there.

Second, Communism has never once failed to bring hardship, suffering, and death to its own people. It has been a disaster everywhere it has been tried; and there's only so many times one can blame that on just having the wrong guy in office, just like you can only blame so many horrid Russian harvests on "bad weather".

In Nicaragua, Reagan helped collect funds from various citizens, foreign countries, the Sultan of Brunei, and private organizations--in addition, Israel sold arms to Iran and some of those proceeds were diverted to the Contras while two heinous regimes bled each other a little longer instead of diverting their attention to the rest of the world. This may or may not have violated the Boland Amendment. Later it was repealed, funding was resumed, and wonder of wonders, Nicaraqua had elections--which probably wouldn't have been possible if the anti-communists hadn't had the aid to stay in one piece through the time beforehand.

"When Democrats scheme from the White House, it's to cover up the president's affair with an intern. When Republicans scheme, it's to support embattled anti-Communist freedom fighters sold out by the Democrats."
--Ann Coulter

Not everyone in Afghanistan was a nice guy. Neither was Sodom, nor Pinochet, nor was everyone in Nicaragua. Neither was Stalin, for that matter, and yet we allied with him in WWII to face a greater threat; and everyone except those who actually sympathize with the Nazis realize that this was a correct and necessary maneuver. That's war, and we didn't have time to wait for the Iraqi, Chilean, Afghani, or Nicaraguan version of Thomas Jefferson to come around before combating an empire that slaughtered more than 100 million of its own citizens and intended to take over the world--it's not exaggeration to say these guys made the Nazis look like pikers.