I’m saying their source code is available to its users for auditing, changing, redistributing without risk of being sued for intellectual property violations.

Closed source means computer programs whose source code is not published except to licensees.

We’re saying the same thing, you just refuse to attach “closed source” to its definition. So answer me this: can anyone freely use it? Can only licensees use it? If the answers are no and yes respectively, that’s closed source.

I’m saying nothing of the sort.

You absolutely are. You’re using the word’s definition (source code available only to licensees), but won’t say the actual word (closed source).