Yeah, I really don't understand that part of the message. It'd make sense if they were lowering prices elsewhere, but now they just... raise them? I seriously don't see how that benefits _anyone_ except Hetzner.
What likely happened here is that they were raising prices due to increased costs for energy and various other costs, and if they hadn't made this change then they would have had to increase the price more, so relative to that it keeps it cheaper for low-traffic customers - and they just communicated this poorly.