An allusion is something you think is correct, but in reality it is not true. If you are disallusioned, that means you have found out that what you thought was a fact is really not true, and you have now discovered reality.
If someone THINKS that a biblical event occurred in a way that is not correct, they have an allusion about it. Some people do not have a correct view of Bible history, stories (parables) and teachings (doctrines), and these issues can be debated and argued about a lot. There are many theories and issues you can learn about. I suggest you read the Bible, perhaps an English translation such as the King James Version, starting with the New Testament book of John, and see what you can learn.
I enjoy reading the Bible, and it has given me great faith and understanding.