It is a stakes based protocol. The rewards pool comes from the inflation on the total Hive supply and inflation dilutes the value of Hive. That's why it makes sense that stakeholders influence the distribution of the rewards.
1 person 1 vote probably wouldn't work because it can easily be gamed/abused. One person can easily control hundreds of accounts.
Just because it is a DPOS protocol and higher HP gives higher influence, doesn't mean lower HP users don't have a say. It is a social network, and it is in stakeholders' best interest to align with the overall users/community sentiment and consensus and what is best for better user experience.