[jpatte]

It's not about what people believed in the past or what they believe now, it's about what they might believe in the future.

By erasing all traces of other religions (and even all traces of other philosophical trends), they essentially make their god "The One And Only God". How could future generations believe in anything else than Allah's almighty existence when apparently everything men did or do is about Him?

They are reshaping History in order to shape the future.