It is an ideology at the lower levels, for the people who have fallen for the marketing ploy. Most remain at the low levels and never get (nor aspire) to see behind the curtain. That's the way those higher up want it... these lower-level people are the foot soldiers, and they are an essential part of the machine. They are meant to be unthinking and obedient, and their devotion to the cause and their superiors (the latter being the representatives of the former) is vital.

Those who do rise beyond that point are not the "useful idiots," and they know (or they will soon know) what the real story is. They may have started out wanting to help the workers of the world unite to form that "dictatorship of the proletariat," but any even somewhat thinking person soon realizes that the worldwide revolution isn't happening. So they start thinking about what "good" they could do with just a little bit more power. That progresses to thinking about how much more "good" they could do with a large amount of power. That, in turn, "progresses" and inverts into using the lure of that "good" to gain that power for themselves. By that point, power is no longer the means to an end, but is the end in itself, with the cause becoming the means.

Any thinking, ambitious person who starts out at the "workers of the world, unite!" level invariably reaches the point where his character is revealed: he must choose between supporting the inversion of power and cause as means and end and leaving the movement and seeing it for what it really is. Any high-ranking person supporting the communist rhetoric is one of the ones with poor character, as he has chosen to seek power for its own sake at the expense of those he claims to be trying to help. Those of sound character will either leave the movement, or depending on circumstances, try to fix things from within.

In the west, where there is still another alternative to communism, leaving the movement is the thing that makes the most sense, but here I think of Mikhail Gorbachev. He was a Communist, of course, who rose through the ranks to become the General Secretary of the Soviet Union. He sought to reform the Soviet Union and essentially overthrow Communism as it was then being practiced. It was the only option; if he left the communist movement, he would be nobody, powerless to change anything, and possibly the next addition to the gulag.

Ultimately, Gorbachev recognized that reforming the USSR was impossible. There were too many within the party apparatus who wanted things to remain as they were. The corruption and power lust were too entrenched. He used his last bit of power (which was diminished by an unsuccessful coup attempt by those who wanted to keep things as they were) to do nothing as the Soviet Union collapsed under its own corrupt and tyrannical weight.

Gorbachev is one of the heroes of the Cold War who, tragically, died as a hated figure within his own country. Russia is less powerful than the Soviet Union, but Gorbachev gave Russians and citizens of the other SSRs a real shot at freedom that would never have come within the Soviet system.