You weren't around for the beginning....
There's a long history between Bushido and KrAzY.
Warlord, who is the GF of Bushido, was one of the founding members of KrAzY.
Most of the folks in KrAzY are still friends with him.
When he split off from KrAzY, some people went with him and some stayed here,
Now that KrAzY is in a bit of disarray, they are moving over to Bushido as they already know a good number of the members.
It's not that this is a training ground, more like Bushido is an offshoot and they are moving over to be with their friends...
Hope that helps.