This view seems to miss the goal of the justice system in the first place. The goals are societal. Any consistency is a means and not an end.
(IE being consistent at all is simply one thing that helps achieve some of the societal goals. It is not a goal itself. A totally consistent system that did not achieve the societal goals would be pointless)
Equality of everyone under the law is an end, not a means. That's not completely synonymous with consistency, but it's not going to be achieved without a pretty high level of consistency.
