The Guardian columnist Glenn Greenwald on security and liberty issues has posted this explanation of sorts.
For reasons I'll let the Guardian explain, all of the comments to all of the columns and articles posted on the London attack were deleted, and the comment sections then closed. I hope that won't happen to today's column here, as the topics discussed here are not really about the attack but the broader debate about terrorism. But it's possible that it will happen again. Those wanting to post comments should be aware of this possibility before spending your time and energy to write one. - Green Greenwald