I disagree, it's functionally a gradient because the label encompasses different assumptions when different people say it. (It's even more vague than the US' "freedom of speech", since it lacks a bunch of case-law precedent.)
You're saying clear-cut objective lines exist--where exactly do you believe they are placed?
Not saying this is the "objective truth", but the OSD does a good job of helping you find a clear-cut line when something is "Open Source" (in common parlor) or not: https://opensource.org/osd/
Again, not everyone agrees with those of course, and I guess that's fine. But I think most software developers who are in the FOSS ecosystem could agree that Llama is not "Open Source" as most people understand the term.