>>17772460 (OP)Outsiders cannot really define who is or who is not a distinct people. If a subgroup of people say they are not Iranian, we can only believe them.
Taken further, if the differences were truly miniscule, it would only benefit them to identify as Persian, maybe with some extra cultural flair as is common in large ethnic groups. To call themselves Kurdish only brings persecution or sidelining.
With that in mind, as it serves no benefit to themselves to identify as Kurds, I think it can be safely said they are a distinct group.