Maybe because they want the 1M sats more than the 5000. If you pay 5000 the money is gone from your wallet. But chances are that for every person that transfers 1M some people will leave all or some of it on WoS which will drive more activities, and fees. My guess.
Discussion
Well it is 5000 in and 5000 out, so in total will be 10k min. π Which is fine but the way he went about this is dumb. Everyone knows Nothing is βfreeβ in this world, especially bitcoiner