Definitely looks like a rage quit.

When everything on the blockchain is so transparent (as evidenced by @jerrybanfield's completely legitimate rummaging through of @riverhead's past), a witness (whether at position 21 or position 121) ought to know that certain things will trigger a reaction. Unapproving a witness will trigger an unapproval of yourself, unfollowing someone will trigger an unfollow of yourself, flagging will trigger flags against you.

If everyone rage quit when that happened, steemit.com would be a very empty place.