According to the search URL wiki, the taxon_geoprivacy parameter should only return observations with system generated obscuration (taxon geoprivacy) applied. If it is not working that way, there may be a bug to report. It is of course possible that the observer could have also applied personal geoprivacy to such observations, but it should not include observations with only personal geoprivacy.
Where there may be an issue, though, is that the system will apply taxon geoprivacy to an observation if there is any identification of that taxon on the observation, even if it is not the community ID. So you may get more species in the above search than are actually obscured by the system.