Maybe Hackpad is a very unimportant and low-priority part of Dropbox, and marketing/PR efforts and expenses over it are so out of the question that they don't care about their open source promise. Not even replying here is a sign of total neglect; I'd attribute this neglect to persistent emergencies diverting resources and management attention, or to incompetence, but not to a deliberate "evil" intent because the only thing to "steal" is a little amount of vague goodwill.