BS rejection reason - PM interview

I interviewed for PM role at a fintech startup in Bangalore. After 4 rounds they are saying since you are the only person who has cracked the final round, we don't want to go ahead with single option. We will interview more candidates and then take a final call.

Could this be a genuine reason? If this is just an excuse to reject, why can't they just say that you don't fit pur requirements. Why keep the candidate hanging?