Do you mean that all hive users would have equal downvote weight? If so, there's a problem with this. It's called a sybil attack. The problem is that one person can easily create many accounts, then vote with all those accounts, magnifying his power. To avoid such attacks, Hive relies on stake-weighted voting, where people at least have to pay for their voting power, instead of just gaming a signup system.

It is worth pointing out that a properly designed reputation system might enable a more democratic system. But this is a topic for a much later date.