I was (perhaps a bit pedantically) objecting to the apparent argument that any shape will do because your fingers will wrap around it. I can think of shapes that you could hold but wouldn't like working with.
I first grabbed a computer mouse in 1984 and I've been using them ever since, without hand pain. How long to I have to wait to find out?
That means that the shape(s) you've been using is/are adequate (possibly for most normal hands of roughly similar size). The ordinary mouse I use at work is symmetric and gives me no issues, but early mice wouldn't work as well for long hours, and I know from experience that tiny "laptop" mice kill my thumb adductors. OTOH (no pun intended), I know people who work *better* with tiny mice, either because they have small hands or because of injury.
Lastly, TFA is about gamers. They mouse like their lives depend on it (some do make a living off it) and it's not unthinkable that the situation resembles other activities like shooting or golf to some degree, where subtle differences in performance and myth complicate gear choices.