Your entire post is right on. They've fed us lies for so long, they're not sure if we can handle the truth. Ba$tards.
The authorities will have decided that it's more important to be PC and try to downplay religious hatred than to give Americans a decent description of suspects so they can be caught before they kill more.
Or to put it another way, the authorities will have weighed the lives and safety of average Americans (ie, those unable to afford bodyguards and live in gated communities) against offending the sensibilities of both PCers and "ethnic enclavers" , and decided that our lives are not as important as not offending sensibilities.
It would be as if they came right out and said,"Yeah, so a few nobodies get shot, maybe killed or paralyzed or permanently disfigured. What difference do they make, compared to the important things in life, like showing how tolerant and understanding and nonjudgmental we are?"
G-d help us if it is Islamic terrorists. There could well be an explosion of rage-by no means directed exclusively against Muslim immigrants-if that turns out to be the case. The betrayal of Americans by a government which refuses to police our borders-and then lies to us if h*ll breaks loose as a result...It could get very, VERY nasty.
Let us all HOPE these killers are basic homegrown "grudge against society" losers, killing at random innocents so they can feel powerful and godlike.