I think what they are trying to say is that if the bots had a world where they could farm things secluded from us players, it would not take up our server slots in the current worlds.

That doesn't work for the advertising bots. No players in the world will mean nobody sees the ads. They will still come.

We also do not want to support botting, so adding a world especially for them would be counter productive. Even if they actually did make the world, nobody would be dumb enough to join because that would mean that they openly admitted to SE that they are breaking the terms of service. Basically, "Hey, plz ban me dood! I are bot."