Maybe this is the source of the confusion between us? If I see someone writing overly convoluted code to avoid an allocation, and I ask why, I will take different actions based on those two answers! If I get the answer "because it avoids an allocation," then my role as a reviewer is to educate the code author about the trade-off space, make sure that the trade-offs they're choosing are aligned with the team's value assessments, and help them make more-aligned choices in the future. If I get the answer "because Bob told me I should," then I need to both address the command chain issues here, and educate /Bob/. An answer is "useful" in that it allows me to take the correct action to get the PR to the point that it can be submitted, and prevents me from having to make the same repeated effort on future PRs... and truth actually /matters/ for that.
Similarly, if an LLM gives an answer about "why" it made a decision that I don't want in my code base that has no causal link to the actual process of generating the code, it doesn't give me anything to work with to prevent it happening next time. I can spend as much effort as I want explaining (and adding to future prompts) the amount of code complexity we're willing to trade off to avoid an allocation in different cases (on the main event loop, etc)... but if that's not part of what fed in to actually making that trade-off, it's a waste of my time, no?