Answer: Because they believed that the revival and full return to the traditional form of Islam would be the way to solve the ills of western and modern trends in society.
The Islamic Revival was a response to Western and secular trends. It was believed to be the way to solve the ills of Islamic and modern societies. The revivalists ideas of this time were known as the 'Islamic Fundamentalism' or 'Radical Islamism' and were seen as the way to return to the purest form of Islam.