I've seen two complaints about the answer. One is that the answer is wrong. The other is that the answer is harmful. Let's look at those:
Wrongness
We don't even need to look at the specific question/answer to evaluate this one. It's simple. We don't delete wrong answers. We've never been in the business of deleting wrong answers. People can self-delete their wrong answers. Everyone else can downvote them. Note that in the deleted answers section of the site helpdeleted answers section of the site help, there's no "it was wrong" delete reason.
If someone really feels a downvote isn't enough (because a wrong answer is highly upvoted), they can leave a comment explaining why the answer is wrong. Anyone reading the answer will also read the comment and can at that point decide whether they put more stock in the upvotes or the comment explaining why all those upvotes are wrong.
Harmfulness
Answers that are actively causing a hidden harm should, in my opinion, be deleted. In most of the cases where it happens, I'm betting it would be someone actively trolling. (i.e., "Q: How do I save my game?" "A: Go to the command prompt in Windows and type format C: /u
").
Notice that I said "hidden harm" though. Looking at the specific question that spawned this, there's no hidden harm. The question is specifically about whether or not alt-F4 is harmful to a save. If the answer of "no" is wrong, it's not causing you some kind of surprise harm. It just means the answer about whether or not it was harmful was wrong, and you can now downvote it and leave a comment about how it was wrong.
Conclusion
It doesn't matter if an answer is wrong. That's what downvotes are for. If the answer is not harmful beyond the extent of possibly being the wrong answer to the very harm the question is about, no action is needed.