It's kind of detailed and murky, but I dug up a couple of links to look at: http://www.open-electronics.org/from-arduino-to-genuino-the-...

http://hackaday.com/2015/03/12/arduino-v-arduino-part-ii/

For a long while, most people didn't understand the turmoil in the arduino market. The competing arduino.srl tried to fork the ide and even the history of the project.

Here's a direct statement from Banzi Massimo: http://makezine.com/2015/03/19/massimo-banzi-fighting-for-ar...