Easy. That's the point of this thread.
All Registrars are governed by the Registration Accreditation Agreement (RAA). If ICANN clarifies that agreement to explicitly forbid domain name warehousing and speculation, the registrar either follows the agreement or loses their ICANN accreditation.
The RAA is currently up for public comment until
August 4th (see links above), if enough people who have a vested interest in this (like any domainer who bids in dropped names auctions) will take 2 minutes and send an email, this garbage might just be stopped.
If that happens, domainers will have a much more level playing field.