Why did Christianity wipe out Gnosticism?

Why did the Church make it such a point to wipe out Gnostics and destroy their gospels? Why did the church feel so threatened by these peaceful ascetics who mostly lived in communities anyway?
It isn't true that Gnosticism vanished long before Christianity was the Roman religion. Gnosticism was the largest religion in the Roman Empire between the 2ND and 3rd centuries according to the New World Encyclopedia. Sects like Manicheanism even continued to thrive into the fourth century. The Mandaeans, Gnostics who follow John the Baptist, still exist in the Middle East and are called Sabeans by Muslims.

Always ask yourself: what will result?
What shall result from any cause, any act of will?

Do you think Christianity would have spread so much if it wasn't for its violent and destructive past?

Of course not. They wanted to expand.

They were teaching a false gospel.

They were threatened by these books. Why? These books took power away from the Church and the Church didn't want to yield power to its followers.

Gnosticism is the more correct perspective from which to interpret the biblical myths, Christians were taught to worship authority, which is not what it's all about. They also exterminated the Cathars who had very similar beliefs around the 12Th century I believe it was.

Power and control over the people. It's like George Bush's "if you are not with us, you are against us" mentality.

Christianity did not have the power to "wipe out gnosticism". Christianity never had any real authority for hundreds of years after gnosticism vanished from history.

Besides, would you really believe that Jesus was only an illusion of a human? What is more easily believed, that Jesus was a human being or that he was a spirit who gave the illusion of being human?

They rejected the authority of the Catholic Church.
And, they didn't agree with the idea of tithing.

"Orthodox" Christianity did not have the power to "wipe out" the Gnostics for the first 300 years of their history. ALL Christians were being persecuted at the time.
The only thing the orthodox Church Fathers did against the Gnostics was speak against their UN-orthodox teachings.