Probably because they are just a hobbyist and not an expert in the field (nor do they assert that they are). Maybe be a little kinder on the internet. It sounds like it was just a minor oversight.
I really did think about whether or not to write that last paragraph. But the thing is, it's the truth. And I think it's going to be more helpful in the long run for authors to know these things.
Believe me, I've been on the receiving end many times and it's made me a vastly better writer and communicator. When somebody stops reading your article because of a howler, it's much better for you to hear why so you can learn from it.
(And you don't need to be an expert in the field to realize that discs that flip are mechanical, or that they don't have a "near limitless lifespan". These aren't exactly subtle mistakes, and it's one of the main justifications presented in the introduction itself.)