How words get into dictionaries. Petitions, direct requests, and (not atypical from transgenders) veiled threats aren’t how it happens. The absence of the word transphobia from any dictionary is not evidence of transphobia. Nor is there such a thing as “the dictionary,” a phrase that basically gave the game away right there.
I asked the organizers if they understood, first of all, the actual process of inclusion of words in a dictionary. I also asked if they even understood that the two examples in their petition – the OED and Microsoft Word – are two largely unrelated kinds of “dictionary.” (The latter, a spellcheck dictionary, is really a lexicon and in all likelihood is algorithmically generated.) Of course I didn’t get a reply.
If you want to do this properly
Submit citations, ideally going back at least ten years, of the word in use. This is a pain in the ass to do, as I know from experience. Googling is an only-barely-viable method.
Update
(2013.07.05) After I sent her the link to this post, Claudia White wrote back and claimed indeed to know how the OED adds words to its “lexicon” and the difference between the two kinds of dictionaries. I wrote back that, if true, her task now is to submit citations. “To paraphrase RoboCop, your move, creep.”