blah blah blah, stop mining so the difficulty will go down for me, don't let the door hit you on the way out
Between the "your dumb because you're paying too much for your 5830s" and this, we know, you really want to scare people to quit
Actually, I don't believe the parent is trying to scare anyone away from mining. He is simply pointing out, and rightly so that depreciation costs represent a substantial cost over that of electricity for mining. Depreciation is hard to get right with mining though as even though we are seeing some of the lower end video gear being sold, (still not many 5970/6990), there is still a scarcity of good mining hardware.
I think another factor though which encourages me personally to continue mining is that I would like to believe that bitcoin has a real chance to succeed as an internet currency. To that end, I would like to remain a part of that.