How on earth is this an objective measure for plugin quality? There's so much you can interpret into these numbers that they are borderline meaningless.
It is objective measure - it may not be a perfect metric, but definitely objective. If there are more issues relative to the number of programmers this means there are either more bugs, users have more questions, and/or just more feature requests (which means - the plugin is lacking features). Also both plugins share the exactly same bug tracker and the same issue filing process, so you can't argue it is easier to report errors for one over another.