It's not only Muslims who want to convert men from other religions to Islam. In India, Hindu fundamentalists have succeeded in converting thousands of Muslims and Christians to Hinduism. I once estimated that the number of Muslims in India should be at least twenty million more than there are now. It's very likely that the reduced population of Indian Muslims is due to conversion (of course, thousands have been killed in communal riots, and as recently as 2002, three thousand Muslims lost their lives in government-supported riots).
I was in St. Patrick's School from 1950 to 1960 and saw a couple of Hindu teachers becoming Catholics. One boy's family (I remember his name was Simon Douglas) became a Protestant and all hell broke loose. The Catholic priests (English speakers from Holland) tried their best to bring the family back into their fold, but did not succeed. Finally they expelled the boy from the school (no doubt because they thought that he would try to convert other Catholic boys to Protestantism).
After the Muslims lost Spain, most of them were either slaughterted or converted to Christianity. It seems that this desire to convert others is inherent and is found in men of all religions.
Nowadays there is much hue and cry about Hindu girls being forcibly converted and married to Muslim boys in Pakistan. Even if the girls were first kidnapped and then forced to change their religion, they have no choice now but to remain Muslims (or migrate to India to avoid being killed by rabid fanatics).