The FBI appears to be concerned that no-goodniks could pull the seal from Wikipedia to make phony badges and documents. But seriously, FBI, the cat’s already out of the bag on this one. Heck, even the FBI’s own site has decent JPGs of the seal that can be found by anyone with rudimentary Google skills.
Wikipedia’s response letter leans heavily on the snark, and refers to the FBI’s “creative editing” and “strategic redaction of important language” in the law it cites. But Cindy Cohn of the Electronic Frontier Foundation sums the whole episode up perfectly when she spoke to the New York Times: “I have to believe the FBI has better things to do than this.”