Re-read it: it says AI is capable of "originality" and does not mention "thought" at all.
You're the one presuming that "originality" requires cognition and hence understood "originality" as meaning "original thought" even though they're different concepts (specifically the latter is a subset of the former).
In your interpretation of that paper you did the exact same logical mistake as you seem to be doing in your interpretation of LLMs - you made assumptions backed only by gut feeling thus taking a leap to reach a conclusion ultimately supported only by your gut feeling.