Exactly, this isn't news or if it is its only new because Linus has gotten much more open and liberal about what he will except for inclusion these days. In the 2.4.x era there were tons of popular patch sets for Linux. Things like alternative schedulers, IPSec implementations, Access control layers, and customizations for vendor specific architecture variants were downright common to have as patch sets.
There were tons of reasons, code quality, license constraints, conflicts with other subsystems, and more often than not someone on the core team just did not like the engineering decision made around interfaces. That person being Linus himself frequently.
I haven never tried to get a kernel patch included up stream but just as an observer it seems the situation is much better than it used to be. The kernel team is larger, and thru the 2.6.x period kernel internals have improved in terms of coupling, the added flexibility has been used to allow more stuff to flow up stream. Linus does not like the BSD secure level model, this guy disagrees, that is all there is to this. Maybe if people think that functionality is useful and not better met by something else Linus will change his mind. That has happened before too. Especially if somone finds it commercially useful and Red Hat or IBM or someone picks up the patches and starts using them.