Did you agree with it before the AI wrote it though (in which case, what was the point of involving the AI)?
If you agree with it after seeing it, but wouldn't have thought to write it yourself, what reason is there to believe you wouldn't have found some other, contradictory AI output just as agreeable? Since one of the big objections to AI output is that they uncritically agree with nonsense from the user, scycophancy-squared is even more objectionable. It's worth taking the effort to avoid falling into this trap.
Well - the point of involving the AI is that very often it explains my intuitions way better than I can. It instantiates them and fills in all the details, sometimes showing new ways.
I find the second paragraphs contradictory - either you fear that I would agree with random stuff that the AI writes or you believe that the sycophant AI is writing what I believe. I like to think that I can recognise good arguments, but if I am wrong here - then why would you prefer my writing from an LLM generated one?