James Woods:
I have sometimes wondered why the JWs did not make this a disfellowshipping offense - particularly when they are willing to disfellowship people for practically anything else, even smoking.
I speculate that this is done for recruting purposes. You're maybe looking at it from the perspective of someone who is already in and wants to marry. The Watchtower may look at it from a different perspective as well. How many worldlies would not join if they were told that they have to convert their spouse or divorce them? What kind of media attention would that bring?
I can but wonder how many of those who already married "in the Lord" and divorced would actually want to marry another witness instead of someone completely different.