Bingo! Adobe has a de facto monopoly on vector and bitmap editing software tools, and it would make total sense for this acquisition to be stopped by the government on that basis. "The government" in this case would be the DoJ's antitrust division headed by Jonathan Kanter [1]. Looks like the process is to send a letter requesting a "Business Review" [2]. It's probably a "fill out this simple 30 page form, wait 2.5 years (max!) and then have your review request politely declined" situation, but I suppose it's foolish to complain before trying.