In July 2012, Billings left the following comment on the blog of fellow Mozilla employee Christie Koehler:
Or, to put it another way, we don't want you two around, really. You've spent months creating drama and attacking anyone who disagrees with you in the most passive-aggressive 'I'm a poor victim' fashion.
Feel free to find the door to more perfect folks who agree with your politics and allowed means of expression.
In the comment, "you two" refers to Koehler and Tim Chevalier, two of the Mozillans who had been vocal in the Planet Mozilla controversy. Billings's displeasure about "creating drama" referred to Koehler and Chevalier's public advocacy that Mozilla adopt a code of conduct.
Billings posted this comment anonymously (signed "A Mozilla Member"), and Koehler posted the text of it to her blog. Many comments on this blog post from Mozillans reflected disbelief that a Mozillan would write such a comment, and insistence that it must be an outsider pretending to be a Mozillan.
Because Billings did not take steps to conceal his IP address, he was soon identified and Mozilla HR was contacted.
Chevalier wrote at the time about the obvious threatening character of "we don't want you around" when addressed from one colleague to others:
These comments were absolutely a threat. Saying "we don't want you around" strongly suggests intent to create a working environment that will be hostile for us, and indeed, on its own, it is a comment that contributes to a hostile working environment. The nebulous "we", as well, is the kind of comment that provokes fear over just how many colleagues of ours "don't want us around".
Mozilla HR treated the matter as an internal quarrel between employees, without any public acknowledgment or apology on Billings's part or, indeed, any apparent consequences. In September 2014, Chevalier publicly named Billings as the author of the threatening comment. As of April 2015, Billings is still employed at Mozilla, where he manages the Platform Engineering Security Fuzzing Team.