I'm not LDS, but I'll stick my neck out here. Religious folk with an exclusive religion believe what they believe is true (myself included). They, next, believe that it completes people and that people are better off with it (either now, in the hereafter, or both). Lastly, out of good will, they go tell others. There's nothing inherently coercive or dishonest about missionary efforts.
Further, we all act as missionaries at some points. When we explain our ideas and hope that the other fellow adopts them, we use the same basic principles. When we do this on a semi-regular basis, either by seeding or by blatantly starting it up, then we are being missionaries without the formal title. After all, everyone has a pet subject (with varying levels of assertiveness) that they seek to put out, whether politics, religion, or something else. We all find value in our beliefs and want to have others share them.
Which is worse, then, someone who cares about others and seeks to explain what they believe is true, or someone who simply doesn't care and would rather let everyone go their merry little way, even if telling (not forcing) them a better way (in their opinion) is an option? Which is more human? I would dare say that it's the missionary efforts.