This answer perpetuates the myth that POST requests are somehow more secure for changing data than GET requests. Even though the question is closed, it’s a top Google hit because Google doesn’t care whether a question is closed.
The answer has gathered a huge number of upvotes, in what seems to be a case of the experts being far outnumbered by the non-experts. The flaws are pointed out in the comments, but nobody edited, deleted, or downvoted the answer as a result.
Is this seen as a problem? What can be done about this? Remember that despite being closed, this still appears in Google and looks rather authoritative to a casual visitor given the number of upvotes. Should this answer or, in fact, the whole question be deleted completely? Or at least marked off-limits to Google?