Yes, an open text channel could be abused and it is only unlikely to be abused if it's public; e.g. everything reads "makecheck said X" and not just "X".
Maybe the right thing is for downvotes to always list voter IDs (but probably not long upvote lists). If I downvote something for "the right reasons" I don't really care if anyone knows it because I expect most people will agree with me. The opposite would be true for someone doing a lot of petty downvoting; he or she would probably be embarrassed and discouraged once everyone can see that the same person has downvoted a bunch of comments for no reason.
One way to find a "reason" for a personal downvote, then, would be to look at everything else your downvoters have downvoted. One of two patterns would probably form: either these people are in the habit of downvoting lots of stuff for no reason, or they seem to be downvoting comments that have common themes.
Maybe the right thing is for downvotes to always list voter IDs (but probably not long upvote lists). If I downvote something for "the right reasons" I don't really care if anyone knows it because I expect most people will agree with me. The opposite would be true for someone doing a lot of petty downvoting; he or she would probably be embarrassed and discouraged once everyone can see that the same person has downvoted a bunch of comments for no reason.
One way to find a "reason" for a personal downvote, then, would be to look at everything else your downvoters have downvoted. One of two patterns would probably form: either these people are in the habit of downvoting lots of stuff for no reason, or they seem to be downvoting comments that have common themes.