Hindu Kings were high class, blessed by Brahmin class.
Big Masses of Hindus were treated low caste. Their treatment was worse than that of slaves. They were outcast, and not even worthy of talking or touching.
Any sensible person will appreciate that if a religion of equality invites them from position of POWER, where is need for sword to convert.
But in their denial state, communal Hindus only honk...islam spread by force, by force, by force.