I'm not saying this is a great state of affairs. But I'm saying that it's so pervasive in daily life that yes, at least part of the blame lies on users for not taking this into account. As a developer it's important to at least try to understand the tools and libraries on which one relies. Relying on magic black boxes is not a good plan on the user's part, and they need to be defensive about this. Too many developers have been more than happy to hand the keys over to the AI assistants and hope for the best.

Also it wasn't completely undocumented, rather it was hiding in not-quite-plain sight. Which itself is a bit duplicitous, but again something that's far from unique on the part of Anthropic.