If it was all so simple as you say then there should have been some indications ahead of time they planned something this awful to us. I don't think it's simple, I don't think it's over. I also think there is little or no evidence of racism because I work with Christian Arabs and none have experienced any harassment at all. The Jews are hiring security guards for synogogues, so it's clear they are feeling harassed but they aren't complaining, they are doing something themselves about it. We have a Jewish doctor working with us, and now we have a security guard, I think the Jews are at far more risk and no one seems to mind anti-Israel or anti-Jew posts. I read people posting that we should pull out of Israel now and let the Muslims have at them but that isn't considered hate.
They "got away" with it because we live in an open society. We do not routinely track the movements of all of our citizens, and feed them through databases to see what connections with proscribed organizations shake out. Nor should we. Proscribed organizations can change from Terror International to born-again Christians in the change of an administration.
However, once criminals do provide the government a reasons to go through their lives, the government can and will do so with a remorseless thoroughness. There are 5000+ investigators on this case. That is 250 per terrorist. You can find a lot of information, quickly, on an individual with 250 people pawing through his life. Which leads to others, and so forth.
Not so. Drooling anti-Jewish posts get nuked here. You haven't seen some of them, because they disappeared within minutes.