Good point! I wasn't aware of SCM_CREDENTIALS either, must have been a while that I read unix(7) carefully the last time.
Overall I think I can see both points in this discussion.
Why doing some limited hard-coded stuff in the kernel if much more fexible functionality can be done in a user space daemon?
I have not worked with Android, but having seen power and other resource consumption of Maemo's daemons (udev, hal, DBus, tracker, what else...) I can understand people saying that Android took a very strict standpoint against user space daemons. Actually Maemo has syslog, but it's not installed in factory devices because it is too resource hungry.
Maybe the truth is just that one size does not fit all.
In a server the most advanced poetterish journal daemon will not consume any measurable amount of resources and the server admin might benefit from all the flexibility and functionality.
On a phone you don't even want to waste the context switches and the code size and 4 hard coded logs are just good enough.
Of course the kernel is configurable. So wouldn't that just mean that the most limited version is in the kernel (didn't Linus say that if it is used in millions of devices it deserves to be merged). But everybody from desktop upwards just configures it out, because they use a full-fledged user space daemon.