Firstly, when I see an extremely light gray comment, I'm always curious to see what could possibly have been so ridiculous as to justify that kind of downmodding, so I'm more likely to read it than I am a positive-karma comment.
Secondly, if it truly was a stupid or objectionable comment, it gives some satisfaction to downvote it, and watch it turn an even lighter shade of gray.
So for me at least, this feature actually encourages the two things it's supposed to discourage: reading negative-karma comments and downvoting them to oblivion.
Firstly, when I see an extremely light gray comment, I'm always curious to see what could possibly have been so ridiculous as to justify that kind of downmodding, so I'm more likely to read it than I am a positive-karma comment.
Secondly, if it truly was a stupid or objectionable comment, it gives some satisfaction to downvote it, and watch it turn an even lighter shade of gray.
So for me at least, this feature actually encourages the two things it's supposed to discourage: reading negative-karma comments and downvoting them to oblivion.