Hadn't heard about this project before; it's a really good idea.
English is not a language that either lends itself well to, or is historically regulated by, prescriptivism (with a few specific attempts that didn't claim universal adoption). Treating it as a language where "If you've heard this novel construct, here's where it came from and what it's related to" is a good way to approach it.
(I liken it often to C++. C++ is so broad that the ways you can glue features together are often novel and sometimes damn near emergent. It's entirely possible to be "a fluent C++ user" and never use curiously recurring template pattern, or consider case-statement fallthrough a bug not a feature, and so on).
Likewise. A really cool site.
The English language has so many little quirks. You can try to document them all, and it's a fun endeavor, but you can't try and document them all.
What you’re saying is probably true of all human languages. I don’t know of any where usage is actually governed by a governing body. Some try, e.g. the French Academy, but they are widely ignored in actual usage.