Millie210,
It isn't that all systems are destined to go corrupt or end up that way. It is that all are susceptible.
But the opposite is also true. Not everyone goes the path of injustice. Groups are also susceptible to the wonderful good people can accomplish.
Go back to the Roman Catholic Church. Is it all bad? Leaving whatever view you might have about its doctrines and about religion in general, how does a corrupt system produce so many good people who do so many good things? We're not talking plain ole JW good, we are talking heroic in virtue like Mother Theresa and others who have made an impression on history, changing the very world itself by the good they do.
There are atheists who have done equally good humanitarian works. Buddhists, too, agnostics, Hindus, Muslims, Native Americans, Jews--we can go on and on. Good is not limited by one's convictions. It is not exclusive to the relgious nor impossible for the Catholic or non-theist.
The difference is that Jehovah's Witnesses are lying, to themselves and to the world. Religions and secular philosophies struggle in a search for truth and justice and claim to be on a journey to these things. JWs claim they are the destination and font of all this as they constantly reset and redesign their end-of-world prophecies to make it look like they are not on the wrong path. Whatever you might think of religion or philosophical world views, there is a difference between being on an honest search and being mistaken and being in denial, covering up your mistakes, and claiming you are the only vessel of truth.
Catholcism, for example, does not teach it is the only way to salvation. It acknowledges that God is not limited by denominational lines when it comes to saving people. Atheists are viewed as equally redeemed as the believer. Jews are not to be proseltyzed nor converted as they are viewed as already on the path to eternal life. True, they are many problems still, unforgivable sins committed by many within, but this is not a religious system that holds much in common with the way JWs believe and act. Can you imagine JWs stating that Jews are not to be converted or preached to?
Jehovah's Witnesses teach us to be always looking for the solution or even claiming to be or have the key to the solution to everything. These other systems teach people to be the solution, even encouraging many to find new ways of doing so, to make it up as they go, even break the rules to do that. JWs teach people to wait for the solution, that they can't bring one. Other groups, religious and non-religious, yes, even Catholicism teaches we are each responsible for being the solution.
The greater sin, in my humblest opinion, is telling people to wait for a future solution, doing nothing, like the JWs. In this way you can see that the Witnesses are very different, not just from Catholicism but humanity as a whole.
An old Jewish proverb says: "Pray as if everything depends on God, but act as if everything depends upon you."