I think this is a case of https://xkcd.com/915/

I always thought that XKCD was something of a Rorschach test: If you're already convinced that everything is subjective, you laugh at the idea of nerds becoming connoisseurs of something with no depth. If you believe everything can be judged objectively, you laugh at how true it is that even something with no apparent variance can hide subtle details that distinguish its better expressions.

Both of those seem silly to me. Aesthetics isn't a fact about the universe, but nor is it something people just make up. Aesthetics is an objective property of how an individual human's brain will react to a stimulus, summed across whatever group-size you want to talk about (humanity in general, some culture/subculture, etc.)

And those brains are pretty predictable; you can figure out what someone's "tastes" will be from their DNA and formative experience far in advance of actually exposing them to the stimuli in question.

Or, to put it another way, "human aesthetics are an arbitrary result; they 'could have' been anything. That doesn't mean you should ignore them—your arbitrary path-dependent values are literally all you are."

(This is just the aesthetics interpretation of the LessWrong http://wiki.lesswrong.com/wiki/Metaethics_sequence, if you're wondering.)

But is it? https://news.ycombinator.com/item?id=9597348

What am I supposed to see in [2] exactly? All of these fonts are perfectly readable at small size.

Try it at a bigger distance. I can notice a difference. Helvetica and Arial make it hard to distinguish the "l"s from the "i"s, while the other two have distinguishing features: a round dot and sloped stem for FF Meta, and the little overhang on FF Unit. That makes the two of them easier to distinguish at a glance.