The Al-Aulaqi Drone Strike: An "Act" of Attainder?

By now you've pored over last week's complaint in Al-Aulaqi et al v. Panetta et al.  I’ve only got one cent to add to the already quite robust discussion of the lawsuit, and it has to do with the last of the complaint’s three claims for relief:

Defendants’ actions constituted an unconstitutional act of attainder because Defendants designated Anwar Al-Aulaqi for death without the protections of a judicial trial in the circumstances described above.  The death of Anwar al-Aulaqi was a forseeable result of Defendants’ actions and omissions.

Here’s one (obvious) problem.   Plaintiffs challenge an unlawful “act” by executive branch officials. The relevant constitutional provision, however, states that "bills" of attainder must not be “passed” - that is, by Congress.  And plaintiffs do not argue that the statute behind the Al-Aulaqi operation - the AUMF - is itself a bill of attainder, or an unlawful legislative punishment directed at this or that individual or group.  Instead, they have invoked the federal bill of attainder clause, in explaining how the named executive branch personnel each violated Al-Aulaqi’s rights. So what’s going on here?  Why the apparent rehashing of the Fifth Amendment claim? I could understand if, given the high hurdles confronting the complaint's two Bivens claims, plaintiff’s counsel might want bolster those counts with something more viable, relatively speaking.  (That is, in the exceedingly unlikely event that the suit ever would make it to a decision on the merits; odds are better that it will be dismissed on threshold grounds.)  But on its face, the bill of attainder claim seems no more plausible than the Bivens claims - maybe even less so, given the mismatch between the Constitution's text and the plaintiffs' allegations . . .