That question was closed by the community by various users. No moderator involvement has been performed on it yet.
As it stands right now, I see 3 people have already voted to re-open that question, so you are not alone in your evaluation of that question.
I would be on the side of the fence where the people want to see this question re-opened. I think people might be taking the computer hardware/software restriction maybe a little too literal? I would like to hear what some of the others have to say. One of the major reasons I see questions like this closed is because of the answer being readily available on other websites (Wikipedia, company website/forums, etc.).
However, since it already has 3 re-open votes, I would like to see the natural site process of the community re-opening the question. I would also like to hear others opinions on why this question should remain closed.
UPDATE: Digging through some of the linked sites, I saw one good quote about the answer to this question. "Why are there 8 bits in a byte? A similar question is, "Why are there 12 eggs in a dozen?" The 8-bit byte is something that people settled on through trial and error over the past 50 years. " (Source)