IMO it's not worth it. It's unlikely a comment on an article will every change anyone's opinion or make them go get educated on a topic. Also many are probably just trolling for reactions from people, so they can troll some more.
I saw an article on CNN the other day and the only thing I posted was "Bitcoin itself is still fine and still here, MT Gox was only a single company. Long term bitcoin will continue to move on". Something like that. The amount of hate responses I got from people calling me a "scammer" or saying "you must have bitcoin huh" or "LOL this is the stupidest thing ive ever read" or "Hows it feel to lose your life savings nerd!".... it went on and on. I was tempted to respond but realized it's not worth it. It was quite shocking to see so many responses like that though to what I thought was a logical post on my part.
It is absolutely frightening the amount of ignorance in the world. And that they take time out to post replies that are absolutely slanted, un-informed, and frankly stupid (lacking any intelligently formed opinion). They take the word "scammer" like it is a catch phrase. lol You are right, replying does nothing. Except maybe help vent some frustration, yet it is not completely positive and more negative posts are found. Maybe those folks were hired by JPMorgan or BOA or Paypal? I wouldn't be surprised.... .05 per derogatory post.