IIUC, the accusation was not to try to remove Alpöge from the paper he wrote with Buckmaster solving the "easier" conjeture, but to exclude Alpöge in the followup paper where Buckmaster review the OpenAI solution of the "full" conjeture.

For comparison, if you offer me to collaborate in a paper about Algebra I may agree to go alone, but if the paper is about Quantum Chemistry I have to piggyback a few coworkers because we are collaborating in that topic for a long time and I already discussed may of the topics and I may even discuss the new paper too.