The majority of Stanford players have already graduated (immediately eligible). The Stanford players are leaving to get FREE masters degrees.
The majority of UCLA players are 2018 signees. They are either the last of Coach Mora's recruits or the first Chip Kelley recruits. Any time a program shifts direction players are going to be unhappy.
The Pac-12 guarantee's 4-year scholarships... coaches don't force kids to the portal.