I am friends with Isaac's dad, and although we don't talk a lot, I am aware of some of the family's thoughts and feelings regarding BYU.  They eliminated BYU because BYU doesn't recruit (expect LDS kids to come), and BYU never offered his older brother so no loyalty.  Probably the main reason is that the Johnsons are normal people who care about their kids.  They read what people are saying, especially on CougarBoard.  After reading some of the nastiness written about him by you wonderful BYU fans, it's no wonder Isaac chose to play elsewhere.  After his mission, by the way.  Apparently missions and not judging and not being nasty are only for those who are loyal to BYU.