Hm. Trollishness, or maybe just being too stubborn to know when to quit. *headshake* I doubt it's deliberate trolling so much as it is someone who thinks s/he's doing a good deed by pointing out "weird" usages, and just doesn't understand why someone might be annoyed by the way s/he phrased that comment.

ETA: In other words, a critical failure on the audience awareness roll, and a concommitant inability to read tone very well.