Characterizing the discussion behind this as "sophistry" is a fundamentally unserious take.
For a serious take, I recommend reading the copyright office's 100 plus page document that they released in May. It makes it clear that there are a bunch of cases that are non-transformative, particularly when they affect the market for the original work and compete with it. But there's also clearly cases that are transformative when no such competition exists, and the training material was obtained legally.
https://www.copyright.gov/ai/Copyright-and-Artificial-Intell...
I'm not particularly sympathetic to voices on HN that attempt to remove all nuance from this discussion. It's challenging enough topic as is.