Nationality is a man-made boundary. GOD says, "let there be no boundaries, make them all Christians" ALLAH says, "establish the Islami ulma irrespective of boundaries..."
So, people fight in the name of GOD. But no Hindu scriptures says about spreading Hinduism.....there is no such thing as conversion..... The riots you see are the Hindu reactions to muslim atrocities...over which the Govt always a blind eye.