It seems like PG wants people to vote on the content with less biases than before i.e. not knowing how it's been voted. If you now introduce the bias of how you

It seems like PG wants people to vote on the content with less biases than before i.e. not knowing how it's been voted. If you now introduce the bias of how you have typically voted for that user, once it again it may affect how you vote for that comment. Each vote is independent of the last vote essentially.