Apple Stole Its Ideas In the First Place
Perhaps. The problem with this line of attack against Apple is that it is irrelevant to the ongoing patent litigation. Whether or not Apple invented the graphical interface, touchscreen, mouse, or anything else has no bearing on the fact that Apple holds hundreds of patents in countries around the world for various technologies and concepts, and it is those patents which Android--or the device manufacturers who rely on Android--are accused of violating.
If Xerox, Palm, or any other entity believes that Apple has infringed on its patents, it is incumbent on them to defend those patents and take that up with Apple.