Well, I think it's more a result of the general indoctrination that of any specific policy.
They see a JW living with an XJW and think 'Cricky, they're living with a crocodile... mmmm.... maybe a bit of matchmaking or "encourgement" will help them improve their lot? They'll be much happier if I help thm get away from that beast...'
So, they go about doing stuff to help the marriage fall over thinking that they're helping out....
I don't beleive there's any specific policy or program, just interfering zealots