Yes rating avocados is subjective. But then again rating the quality of any fruit (or food) is subjective. Still if you look at a list of people's favorites the same names will come up on the top over and over again.
Keep in mind though that the favorite cultivars of commercial growers does not have much to do with what is people's favorites. They choose mostly based on productivity, shelf life, uniformity, looks, disease resistance. Taste is only one small component for them. A lot of people wrongly assume that because a certain cultivar is the most widely grown that it must have the best quality, in terms of taste.We know this is not true with Tommy Atkins avocado, or Red Delicious apples (the old top selling cultivar), and i don't think it's true with Hass either. But it's not surprising when there are so many hundreds of cultivars of avocados.
The fuerte was the top commercially grown avocado for a long time before it was supplanted by Hass. There is evolution even in the Hass. They just keep calling it by the same name even though the trees are different than the Hass from decades ago, . This is just because the name is so implanted by now in people's minds and the marketers don't want to move on to a different name. Remarketing under a new name costs money and time to get consumer approval.