Calling someone a troll has become a method to completely disregard their opinion without having to address it, similar to calling someone a Nazi of fascist which appears to be very popular these days.    If you have no other valid response you can just use one of these words to describe the other person and then go about your day with a sense of smug moral superiority.  This is at best intellectually lazy but more realistically, completely disingenuous. The mainstream media has been doing this a lot recently.