Why? Snowflakes don't have a "self", and yet they organize as a result of the inherent properties of water.
I think it's important not to mistake the limits of the language as somehow limiting the thing itself - by "self-organizing", I simply mean a system that pulls itself up by its bootstraps, with no external force driving it. The self-organization of snowflakes or quartz crystals neither implies nor requires agency, intelligent or otherwise.
But, er, we have a disagreement on the definition of "self organizing complexity".
In everything I have read on the subject, self-organizing complexity occurs in closed systems - moreover, autonomous systems. Concerning evolution, Rocha's work is most informative:
So that's the story. The intricate shape of a single arm is determined by the ever-changing conditions experienced by the crystal as it falls. Because each arm experiences the same conditions, however, the arms tend to look alike. The end result is a large-scale, complex, six-fold symmetric snow crystal. And since snow crystals all follow slightly different paths through the clouds, individual crystals all tend to all look different.
If it were shown that complexity in living systems is the result only of self-organizing complexity, then the Designer's role in ID would be limited to the inception algorithm and initial conditions - not punctuated here and there to give rise to functional molecular machinery, species, etc.