I'm not sure if that is the reason. It is rather puzzling. A lot of Google Products work just fine, say Google Mail. On the other hand, the whole Google developers site is inaccessible (including everything from Android, to their Chrome/HTML5 information site etc). US law clearly requires no such action on their part.

The don't earn money by letting packets from Iran route to their network; The people who could be losing money are their customers who's content is restricted.