I don't know. Do you think it is mere coincidence that all (IIRC) of NHC winners the last couple of years were all grain brewers? Or better yet why don't commercial breweries switch to extract if there really isn't any difference between extract brewing vs. all grain brewing?
Extract is significantly more expensive per gravity point than grain. And still there are SOME pro extract brewers.
Regardless, the question is not if extract makes better/worse beer but if it is a d-bag move to slap someone down because they are starting out with extract.
Absolutely it is a D-bag move to bag on someone who starts out extract brewing!! That is how most of us started and I think it is the preferred way of learning how to brew.