Because I'm a masochist. And if there are questions I can answer reasonably, then I'd like to. If someone asks "which console performs better," I can answer "neither." If someone asks if you can play non-lethally for the entire game, I can answer "kind of." If there's a valid question about my opinion, I'll respond if I can, just like I will in our own comments. I would prefer to be as open as I can about my reviews and the process at the site I work for, because I want there to be integrity in how we go about it.
But how should I respond to people who act like assholes because I either say something about something they haven't played to the degree I have that makes them uncomfortable, or because I have the audacity to use a word like "holistically?"