First, "Muslims want to convert" is bit of an overstatement, not substantiated by facts. Accept the euphemism "Muslims like to deliver the message." Even orientalists agree that there hasn't been organized proselytizingconverting - forcefully or otherwise - infidels to Islam, except possibly for Spain under Al-Mohavids. In fact, if you read Hans Kung, a Christian theologian and orientalist, he goes so far to say that Muslims rulers (especially those in Syria) "disliked" conversion to Islam, for political reasons.
Secondly, missionary works is a part of every religion, even secular religions like say liberal democracy. There is no guarantee that every missionary expedition has always remained faithful to the jurisdictions of delivering the message and the message alone. However, such transgressions (coercing people to change their faith) are not a norm. To judge of all Muslims by transgressions of a few zealots - speaking hypothetically - is unwarranted.
It is an oversimplification of any religion to reduce it into a matter of identifying the right God. Every religion has a worldview, even the godless religions. When Muslims preach, they speak not only of God but also of the Judgement - a worldview based on mankind subjected to a trial, the ephemeral nature of this world and the permanence of the next world. The question of how to spend ones ephemeral life is inextricably linked to the worldview. The answer in a nutshell is in following the Quran and the Sunnah. Taken this way, there is no place for religious relativism i.e. every religion is as every other religion.