Fundamentally, it doesn't.
AltBeacon (as far as I can tell) exists simply so Apple has a harder time using their bullying legal tactics against people.
Specifically, the folks behind AltBeacon (RadiusNetworks) previously made an open source Android library that allowed Android apps to easily detect and use iBeacons.
Apple threw their lawyers on them, and they pulled the Android library. Presumably, Apple will have a harder time being a bad citizen against AltBeacon.
To be honest, I think that is fair. I can't imagine this is preventing Android from using iBeacons. My opinion would be that it is preventing profiteering from something Apple a) has a trademark on and b) might want available for free.
I assume AltBeacon is the fallout from this. It would be nice if Radius and Apple could work together on Android support. Could be likely that its happening in Android OS already?
Are there any non-commercial, open source iBeacon-compatiable libraries out there for Android? It would be handy to know if there are.