@JonathanBeardsley: I'm still unconvinced by this. I'm seeing at least two elephants in the room:
1) American speakers would make it all about blacks, and everyone from outside would see it as a waste of time (this is the ICM, not the AMS JMM).
2) Diversity activists uninterested in mathematics will get excited about ICM, and will start stalking it on social networks; experience shows that they will get disappointed in a matter of months and there will be a major blowup, with everyone getting called a nazi and angry letters flying around. I know this isn't how it should be from a logical pe…