Nobody is smoking crack or anything like that. There's more than one way to skin a cat, despite current trends in homebrewing over the last several years. The thing is called a "secondary fermenter" for a reason, and the reason is that we used to do quite a bit of fermenting in it.
Some folks, especially among those that have been brewing for many, many years, still like to rack early from the primary. You get your beer off the protein trub and get a clean yeast cake in the bottom of your secondary. Oxidation isn't a concern, since the beer is still actively fermenting and will purge all the O2 out of the vessel quickly enough. Neither diacetyl nor stuck fermentation are a concerns, since you still have plenty of yeast in suspension when you rack. Autolysis isn't any more of a concern than it is with the currently growing fashion of leaving beer in the primary for some weeks. The only disadvantage over any two-stage fermentation is that you have more sediment to deal with in the secondary, but it's all yeast and easy enough to work around.
Now, you run into problems when you want to rack after your fermentation has slowed down too much but not finished. That's when you get diacetyl problems because you take the beer away from the yeast right when it's trying to clean up after the party, and you don't bring enough yeast along to the secondary to finish the job.
I don't rack early, anymore, but that has to do more with habits deveoped during a time when I might have to leave my beer in the primary for more than a few days and the knowledge gained from doing so. Now, that same experience has become the common teaching. When I started brewing, it wasn't.
No one is smoking crack or anything like that. They are just doing things the way they've been doing them for quite a while, and they've been doing them that way because it works just as well as anything else.
TL