Absorb all "our" IP without consent, in doing so remove "our" own source of revenue, and then repackage it as their own product. Not really fair use IMO.

How does that work? Is it a kind of infringement without substantial similarity?

I find it hard to think of a reasonable analogy. But it's like coming into your house, stealing all your belongings, and then building a new house with all your shit inside and then selling it back to you.