Let's assume for the sake of simplicity that the debate concerns a non-subjective question, so it has a right answer, only it is unknown which it is.
The best outcome for HN is if we as a community converge on the right answer.
Now if someone brings argues poorly, but for the right answer, and then someone comes along and crushes the poor argument. Then the counter-arguer "wins" and succeeds in humiliating the "opponent". But the the wrong answer wins, and that is bad for the community
If on the other hand, someone comes along, reinforces the poor argument, and then brings a weak counterargument, then that gives the right answer a better chance of winning.
The best outcome for HN is if we as a community converge on the right answer.
Now if someone brings argues poorly, but for the right answer, and then someone comes along and crushes the poor argument. Then the counter-arguer "wins" and succeeds in humiliating the "opponent". But the the wrong answer wins, and that is bad for the community
If on the other hand, someone comes along, reinforces the poor argument, and then brings a weak counterargument, then that gives the right answer a better chance of winning.