This is a code of conduct for RegistryPro, the .pro registry. It does not apply to Registrars and is not included in the registry-registrar and icann-registrar contracts.
ICANN is also obligated to treat all registries equally. So if they tried to impose a warehousing clause on registrars, it would have to be for all gtlds. And we all know that there are several registrars that exist solely for the benefit of a single owner.
It also is not clear that these registrations even qualify as "warehousing" since most are being developed as bona fide websites. warehousing implies that they are being placed on a shelf gathering dust.