The Comments Policy has been updated. As stated in the policy:
No threatening commenters with physical violence; no threats of any sort. No attempts to violate the civil rights of other commenters.
We try to keep the policy as minimal as possible, and we don’t anticipate any problems of this kind. But we decided to make it a rule that it’s not okay for people to threaten each other on the site. That’s going over the line. We don’t want you to worry about it, though. Just relax and keep commenting.