In particular it's not a case of malicious spreading of misinformation, it seems that in the case that the hoax worked the lies were deleted.
Rather it's a case of abusing a public resource. It feels to me somewhat like training a group of school-children to play Rugby on a village bowling green. Sure the damage to the grass will be undone over time, and sure the chance of knocking over any real old ladies is very small; but it's still an irreverent gesture that shows a dangerous lack of respect.
In the real world we have checks to make sure this kind of behaviour doesn't get too out of hand; on the internet we've so far managed to avoid the need. I hope that continues.