I am a programmer. It’s mostly something used by some “web programmers”, AFAIK. Specifically those connected by the likes of people using Wordpress. It is not academically accepted terminology at all.
All terminology is “odd” to those who are unfamiliar with it. Every discipline uses terms that may seem odd at first.
Because it’s not how a slug is defined in Home Assistant; it conforms to the general practice of employing lower-case for almost everything in Home Assistant.
A quick look at your post history reveals you’ve pretty much done nothing but bitch and moan since you got here. As a programmer you could help out by improving things. Or maybe you would prefer OpenHab?
Look better, and bitching and moaning is not the same as saying what needs to be done. I am saying that whoever feels responsible for this needs to hyperlink words like “slug” to a glossary.
Everyone can submit additions/modifications to the documentation. If you believe it could benefit from your suggestions, free free to submit a PR with the changes.