I would like to hear others' opinions as well. I guess for me it's a simple mechanism shared with many other social sites. A series of downvotes without explanation demonstrates the zeitgeist disapproves. Maybe the reason why is obvious, maybe it's not and thus deserves elaboration for the sake of everyone reviewing.
That'd be a stronger argument if there was an actual up/down vote count visible. Right now, there is not one - for users other than yourself, all you have is "positive/not" indicator.
So if you see someone's grayed-out comment, it could be a single disagreeing user, or hundred of them - you have no way to know.
Comments here only go to -4 before becoming dead and hidden by default. So if you're seeing a greyed out comment, at most four people found it disagreeable enough to downvote, and no one felt like upvoting it. Or there's been a lot of downs and ups but it balances out to, say, -2.
As our species looks pretty ill fitted in its niche these days, the zeitgeist is usually about preserving paradoxes at all costs to keep status quo. And that's reflected here pretty strongly. Much of what's come out of SV appeared at one time beneficial, and now it looks like the industry has shifted to dystopian. The zeitgeist that enforces that may be lost.
