It's to compensate for the effect where they are still a bit of a yes man. Way, way better than they were several models ago where they were pathological about it, but still a bit biased in the direction of explaining why you're right. I know I'm not right. I don't want a neutral summary, I want an interesting discussion of what's wrong with my idea and why.
If I were operating in a field in which I was already an expert, or in a field that is more strongly opinion-based anyhow (e.g., philosophy... it isn't particularly clear that being an "expert" in philosophy has any strong impact on your chances of being "right", for whatever that even means in that field), I might ask for something more neutral, but I know I'm not.