Probably because your comment didn't add anything to the discussion. There's somewhat of a culture here of downvoting "Me too" or "+1" type content-free comment

Probably because your comment didn't add anything to the discussion. There's somewhat of a culture here of downvoting "Me too" or "+1" type content-free comments, and even jokey one-liners that don't progress the discussion. My respectful suggestion is that when you want to comment, try to say something that uses your own experience or opinion to add something to the discussion, rather than to mirror or agree with some point in the article or in a comment. I'm far more likely to upvote something that makes me realize something I hadn't already thought of.