Looks like this entry on the ComiXology FAQ may require a little updating;
Why can't I find DC or Vertigo books on the Kindle Fire app?
Last Updated: Apr 30, 2013 04:54AM EDT
Currently, DC Comics and its imprints are no longer available for purchase on our Fire app.
You can continue to access the DC Comics that are in your comiXology library. Plus, the comiXology app on the Fire syncs from the web so you can read comics purchased through the web at www.comixology.com.
It seems that last week, that changed. The ComiXology App on the Kindle Fire now lets you purchase DC Comics in-App.
There you go folks! Fire up the fire! So… what was all the fuss about? It's been a year…