I admit it's a little odd. Relatedly, the UK also instituted a similar laptop ban as well. If not the laptop bomb threat, then what do you think it is? http://www.wired.co.uk/article/uk-laptop-ban-flights-explain...
It could also be a leg-up to American carriers competing on those routes. Another commercial option is a tactic to require implementation of security practices that involve American-made equipment.
I'm sure there are many other possibilities that make more sense than the public explanation, which only seems to make sense if we assume the people protecting us are incredibly stupid. I don't think they are, so the public story is probably just a cover.
Perhaps, they wanted a more comprehensive laptop ban but were stopped by someone.