Can I point out that deleting a comment once proven wrong is a form of admitting one is wrong. The conversation is between the involved people at first. If one points out what they think is an error and the other points out that there is no error and the person is wrong, the comment should be deleted. The objective was to inform the author, but the informant was himself corrected. Everyone involved knows what happened, it doesn't serve anyone to keep the comment. The goal is not to keep something around to show that any person was wrong, it is to improve inaccuracies in the post. Keeping these comments around if they are wrong only serves to embarrass people with "see, people disagreed and they were wrong". That's not the point. It is spiteful and arrogant to force someone who disagreed with you when you were right to be put on display as an example of them being wrong. dmckee saw he was wrong and admitted it by removing the incorrect assertion. The only way he could have failed to admit his error is if he had left it there and either said nothing or continued arguing the same point. But that's not the case.
It should also be pointed out that had it been the case that he had deleted the comment and left you only with the comments from others that corrected it, other readers would see a response comment, not see the original comment and think "Oh, the other person must have realized they were wrong and removed their comment". The only problem you seem to have arises because you followed up his actions with a broad accusatory statement that intentionally attempted to further humiliate the person who disagreed with you. It was revenge (whether or not you intended it that way, this is the common unconscious motivation for such actions). They stood against you and tried to belittle what you said and in response, you attempted to point them out as fools. It occurs to me that had you not opted to act out of revenge and spite, there would be no issue.
The removal of the comment was justified and the most reasonable course of action. When the objective is not to point out someone's folly and only to improve the content on the site, it becomes logical that anything counter-productive to this goal be removed. The comment was wrong, it was removed. Keeping it around does not improve the quality of content on the site. Had the comment been correct, it could be left there until a corresponding change was made in the post. Once the issues addressed in the comment are dealt with, right or wrong, it can and should be removed. Obsolete or wrong comments only add to clutter and confusion. And for the record, I do strongly advocate removing correct comments if the issue was dealt with. The objective is not to showcase that one was correct in pointing out a fault, that is just as arrogant as forcing incorrect comments to remain. The correcting comment should only stay if the issue was not fixed in the post.
You can fight against this policy all you like, but the idea is to have good and correct questions and answers, not to have records of the myriads of discussions that led to a good answer. We are not here to show how well we can correct other people nor how often other are wrong. We are here to present correct answers to questions. If a proposed correction is wrong, there's no benefit in having it remain. If you don't like it, nobody is forcing you to utilise the SE network.