Definitely.
It is more akin to SEO spamming than black market spamming, though. They're polluting NPM in the same way SEO farms spam Google. It makes life difficult for everyone, but it's still a gray area in terms of legitimacy. Which is why nobody really talks about it.
I don't know if this is true, but if it were true you'd have a veritable "tragedy of the commons" [0] situation were privatization of (some) gains leads to the creation of negative externalities for the rest.
If incentives were aligned differently, different results might have resulted. Probably with different externalities (or unintended consequences).
[0]: https://en.wikipedia.org/wiki/Tragedy_of_the_commons?wprov=s...
Should we treat them as spammers and polluters, then? Because if what you describe is true, that deserves to be called out and mowed to the ground.