I think in some instances, and they only use the quiz on some of the articles, this is a good way to filter the idiots, but on the negative side I wonder how many people forgot the intelligent thing they had to contribute because they had to spend time and mental energy completing a quiz. I hope this doesn't spread beyond serious things for serious people , it is very poor UX to ask users to jump through hoops and sp…
If they forgot the intelligent thing they had to contribute then it wasn't intelligent to begin with - it's more likely to be a knee-jerk reaction. If people read the article properly they'll already have taken more time than would trigger a knee-jerk reaction.
It's highly likely I can recapture the thought by stepping back into the environment in which it occurred (in this case skim re-reading the article I imagine), but honestly I don't tend to comment on ephemeral sites, rather post on communities about commenting. It seems more interesting/useful