The list is interesting to be sure, but as with most linear rankings of large datasets it leaves lots of room for debate. But I think that's the point. It's not meant to be used as a rhetorical sledgehammer to silence discussion the way you have used it here.
It's kind of shocking how many of them have an actual monarchy still, with real actual powers over the government despite claims that they are mostly symbolic. Top of the list, Norway, still has a King. New Zealand, still a colony with a King. Finland and Iceland actually have elected presidents. Sweden, curators of the democracy ranking list, still have a monarchy. Each monarch claims they are only symbolic, but if that's true and these countries are truly the more perfect democracies they claim to be, one has to wonder why the people have kept such oligarchs in a position of power over them. In some cases the power seems to have only passed from the monarch to the parliament out of custom, not actual legislation or constitution.