Maybe you already know this and have discarded it (if so, no worries), but for what it's worth, this is my perspective on these things: Some people, in some contexts, use words like a laser — very specific, very targeted, with precise meanings, etc. Other people, other times (perhaps most people, most of the time?) use words more like ... a bucket of paint. Words are sloshy and approximate and about as precise as trying to sign your name using that bucket. Each has their value.
Inevitably, a laser-minded person talks with a sloshy-bucket person and misunderstandings ensue.
In sloshy-bucket land, I think "open source" has various connotations — a sense of community, encouraged contribution, being able to build it yourself, improve it yourself, etc.
And I think the commenter, in broad strokes, was saying that Google is not upholding those various virtues that are often associated with "open source," so felt the term was not a good (sloshy) fit.
In particular, I do not think they were asking the question you say they were asking.
In this space, it seems like there are both too many terms (so people rather just pick a popular one and over-apply it) and too few (so you can never find one that quite says what you want). Such is life, I guess. Maybe "open sourcey" would be good, to indicate it's talking about a hand-wavy vague "ness" rather than a particular nailed-down definition. "Google isn't being very open sourcey"? ¯\_(ツ)_/¯
Anyway, all this to say: in the ethos of trying to take a charitable interpretation of people's words, I think it's good to consider the bucket-of-paint possibility, before jumping to corrections and yes/no determinations.
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Edit: It occurs to me that originally I misinterpreted you as being persnickety, when perhaps you were just trying to answer the question you felt they had asked. Sorry!
Note that I did not write the original answer: I answered to you :-).
> And I think the commenter, in broad strokes, was saying that Google is not upholding those various virtues that are often associated with "open source," so felt the term was not a good (sloshy) fit.
Totally valid! And I like the idea of considering the "bucket-of-paint" possibility before saying "no you're wrong". But on the other hand, sometimes it's worth agreeing on the meaning of words while discussing something.
I feel like I actually happen to regularly be on the bucket-of-paint side. I will often simplify the part of the discussion that I feel is not relevant by saying e.g. "okay this solution is bad, so if we look into this other solution we have to think about ...". And sometimes people really care about starting a discussion saying "by saying it's bad, you make it sound like whoever would think about it is stupid, and that's extreme. This solution is not necessarily bad, because in some situations it may work even though it is suboptimal". To which I tend to say "sure, I said it was bad as a way of saying that we seemed to agree that we would focus on the other one".
Until this point it's perfectly fine for me. What frustrates me is when the discussion continues in what I feel sounds like, e.g. "no, I think that your saying it is bad reflects that you disrespect whoever would think about it, and you should never have used that word in the first place. I am not sure I can ever have a meaningful discussion with you now that you used this word in this sentence, even if you later admitted that it was an oversimplification".
Anyway, communication is hard :-)