Most Helpful Girl
It mostly just shows that they have no points anymore so they're only hanging around to be smarmy and comdenscending and pretend to still have the high ground when they dont
Most Helpful Guy
I wouldn't mind them correcting my grammar if they were also making valid points in the argument. If they were talking complete shit and then called me out on my grammar, I'd assume they were just trying to distract from the fact they were losing the argument and therefore trying to attack me on something irrelevant to the topic.
However I've corrected people's grammar in arguments before. Maybe I'm just a dick, but unless English isn't their first language, I can't take them seriously in an argument if they can't even construct a proper sentence.