as indian nationalism began to develop in the late 1800s and early 1900s, why were two different organizations created to fight for the rights of india

The indian nationalism was developed as a concept during the indian independence movement against british empire.

Around 1900 was part of the british empire but by the end of 1947, India had achieved the independence.

The indian nationalism does continue to strongly influence the politics of india but there is a strong opposition to the Hindu Nationalism which represent the expression of social thought based on the native spiritual and cultural tradition of the indian subcontinent and by the other side there is Muslim nationalism based upon identity of Islam.

For the reasons explained before there were two different organizations.