The Roman Catholic Church

I believe it was general.

The Church was corrupt from the fall of the WRE, to the 1600's.

The Church was barely existant during the fall of the WRE. Much less a corrupt, omnipitant, controling organization. The Church wasn't generally corrupted because it was so religious. Grant it, it was sometimes overly vigerous when it came to spreading Christianity and many times supported atrocities an such that could've been prevented. But Cardinals were not taking bribes or anything.

Sadly though, as we all know, power corrupts and eventually it became that corrupt establishment that we all knew and loved. And for that corruption the Catholic Church almost died. Fortunaly, the Pope is no longer having orgies in the Vatican, so I think all's well as ends well.

They excommunicated the people that sacked Constantinople. Then when they saw all the money they withdrew that excommunication

That's no what happened at all because the Pope doesn't excommunicate 10,000 people on a whim. I mean come on, in their mind that was banishing them to Hell and suffering for eternity.
They revoked the excommunication because it was rediculous, not because of the money that the soldiers mostly kept anyway.

Anyway, the wealth in Constantinople was hardly anything compared to the Church.

lol no. the pope flipped out on them because he had told them that the Byzantines were their friends and not to harm them in anyway. he even told them they would be excommunicated if they sacked Constantinople when he heard they had plans to do it. He then proceeded to excommunicated them, then coincidentally, right as the gold started to flow in, he decided to withdraw that excommunication. It was not a ridiculous excommunication either

Of course, the Pope wanted the Byzantines to work with them and all. But sacking a "heretical" capital during that age wasn't worthy of excommunicaion. In fact in any other case it would've earned them praise. He couldn't banish them to Hell for an eterniy, the money was coincidental.

Many things but I think the biggest effect was the holy crusades.

True, but what about the fact of a centralised power in Rome, where the Pope could contain heretics and heathens by a similar belief?

that too, it was sickening how they tried to convert the whole world to Catholicism by military force, I personally believe Catholicism was a scheme to make people more obediant and never question authority, because imagine if the Pope did something that killed thousands based on different belief(*cough *cough The holy crusades) the citizens would not say anything against it because that must be 'what God wants because the Pope is doing it', no uproar, no riots, no questioning authority.

Actually, if there was no Catolicism, Europe would never rise from the Dark Ages, it was only because of the religious unity within Europe that the barbarians didn't survive for long after the fall of the WRE, the crusades were caused by the Byzantines actually, they called help for the Pope because they were being destroyed by muslims, so the Pope saw fit to send a campaign in the Holy Land, for most people it was a way to start a new life, until Saladin came and took Jerusalem.
The Church wasn't bad for catholic people, only after the crazy inquisition that it became a joke.

It was not "heretical" the Byzantines had been the crusaders CLOSEST ALLY SINCE THE FIRST CRUSADE. Hell the Byzantines losing to the TUrks was the reason the crusades began in the first place. The Pope sent a message explicitly warning them that any attack on the Byzantines would result in excommunication. So when they sacked Constantinople (because Constantinople was the richest city in Europe and they were not getting paid not because it was "heretical") he stood by his word. The Pope NEVER withdraws an excommunication. He only withdrew this one because he wanted to continue to see the money flow into Rome