If there were no missionaries or preachers etc, then no one would know about religion/s. Jesus told his followers to share the word of God, so they did. The same with all the other religions. It's a competitive market out there. Preaching began with the origin of religion so therefore forms an integral part of what religion is. If no one ever preached religion, we'd all be going to hell.
Or comming back again to get it right next time, or going to the dark place, or having a hot cocoa with the devil, or...or...or...