The lesson here is just because its on the internet doesn't mean its true.
In this case, the author, while supposedly knowing his stuff apparently has a diminshed sense of hearing, likely genetic.
There are people who can never make a 3 point basketball shot. Luckily we can see that many people can.
There are feats aplenty that humans can do that if we could not see we would not believe.
Its no different for the ear and ability to hear and discern. Many can hear far better than they realize. Many can't. Far more difficult to tease out the truth since we can't "see" hearing.
But I will tell you that when using a good entry level high-end stereo system cable differences can be heard quite easily by most people. I've setup up many friends audio systems and demonstrated to even more so I know this from experience.
If sound quality is important to you (this is a hobby after all) then you will seek out a high end audio system and let your ears decide.