You're right that rsync's comment does not deserve a negative score. (I suspect that somewhat overwrought language like "I want nothing to do with" tends to attract downvotes from people who already disagree with the opinion being expressed. But this is about as minor a case as you can get.)

All: when you see a substantive, civil comment that's unfairly faded out, it's good community practice to upvote it back to par. In most cases, users already do. But this practice is more important now that we've made some downvotes more powerful.

When a comment has been downvoted unfairly, simply upvote it and keep your own post focused on the topic at hand. If instead of its first sentence this one had said "I agree", it would be a very good comment instead of a mixed bag.

A simple "I agree" or "good point" is a more effective way to pipe up for a downvoted comment than going off-topic is. Let fair-minded users notice the situation for themselves.