Past studies into warfare attribute the aim of war as to change the will of one's enemy.
Too often today, those who live in security more closely associate warfare with a handful of battles and spectacular events causing death suffering and misery for a 1-2 yr period and then resuming to some reasonable status quo. Yet far too rarely do we associate the strategic battles with actually changing the will of the enemy.
Consider the socialist democrats and what they might consider their loses. I dare say they have not nor probably will not change their will until far more devestating consequences ensue upon them personally. I suspect there is a far greater likelihood of a lunatic fringe militant dabbling with firepower with an anarachist/socialist bent performing these murders than otherwise.
I'd say the culprit hates the "War on Terror" and feels as though he/she is successfully rebelling and changing the world with their behavior.
One interesting facet is the"I am G*d" signature, which is proof positive the murderer is not if God. Again, an indicator the murderer is of a more liberal radical ilk and seeks to counterfeit their behavior in open rebellion without accountability.
Insufficient grounds exist to prove these summations, but IMHO it offers a far better description than an angry white male. IMHO, it's a Janet Reno wantabe, who has dabbled in the occult, probably served a little active duty or along those lines, perhaps Wiccan, and thinks they are outside suspicion.