Not sure if they can, but if they did you would be "clarifying" something that doesn't exist anymore. It's better in that case to edit the comment and add a cla

Not sure if they can, but if they did you would be "clarifying" something that doesn't exist anymore. It's better in that case to edit the comment and add a clarification underneath, just like OP did. The problem is that people who downvote do it in a "fire and forget" manner.