I think, rather, the gp was implying that the above was being elitist/classist.

/s indicates a "closing" sarcasm tag.

He edited in the /s after the fact - and besides sarcastic comments don't add any value to the discussion.

That may be the case for most. In this case, it could be argued it does. If one address the parent is being classist (subjective), this comment does well to highlight it.

The /s was pretty clear before the fact too.

Oh really? Cause he made effectively the exact same point you did.

sarcastic comment added the same value your comment did...