I love how you intentionally cropped off the first two words of that sentence, try to make out that their 30 word side note was actually the whole point of the 800 word article, and you STILL didn't manage to make them sound as malicious as you wanted to.
"give us a hint" - "Stop begging!"
As I say, you're clearly coming into this with a strong unjustifiable bias, I can tell because you're forced to use words like "smear", "parasite", "exploiting", "beg", "indentured servitude" - it's a cover for the cognitive dissonance.
But if you genuinely would like a discussion about the pitfalls of the funding models of open source, yeah it's a reasonable question that has never been satisfactorily answered. There are whole PHD projects on the subject, and nobody's cracked it. Giving money to open source projects is difficult for many reasons - ranging from tax treatment to geography even to legality. Providing services is somewhat easier, but in many companies in some countries even that comes with geopolitical legal issues. Marketplaces only work if you have something to barter, and if you would like to contribute to the freedoms you enjoyed, it's hard to make that work in a marketplace model, not to mention that even providing people the option of donating money for a product comes with overhead (legal / technological / service / financial network / server etc).
If you would like a discussion about ensuring abstractions over the services you use, sure, I'm here for it. Of course, it's hampered by a lack of consistent interfaces, and in some cases interfaces that ensure they can never be smoothed over. But that sounds like a cool open source project - in this case, I guess it would be an anyhub kind of deal that can serve images for different use cases, paired with a DSL for defining a resource (that can generate a dockerfile / docker compose file, in docker's case). Of course, serving images isn't free, but you've cracked the problem of funding models of open source, right? Right?
And you mention indentured servitude, loaded though that phrase is, it's also a poor analogy. Tax would be a closer match. You depend on open source and make money off it? Great. Giving open source a cut of that pie in some way seems the morally right thing to do. How you do that is up to you, but telling people they can use your service then pulling the rug while simultaneously ghosting them? That sounds kind.
You know what, I think you're right - it's so much easier to lambast someone for daring trust or daring to express concern than it is to do anything meaningful to improve the landscape.