The first statement doesn't in any way drive the second statement. Yes, you're not based on a US Core profile. That doesn't mean you can't constrain to US Core Patient. What's the reason you don't want to constrain? If you don't have a good reason, you may as well constrain - because you know that once US Core does have a generic Observation profile, it's going to demand the use of US Core Patient.

Existing Wording:

US Core does not offer a generic Observation Profile. For this reason, SDOHCC_Observation_ScreeningResponseBase_1 does not restrict Observation.subject to US Core Patient Profile

(Comment 120 - imported by: Robert Dieterle)