1) The power structure is terrified of the possibility that there will be a popular groundswell of anger against moslems.
2) The power structure is also unwilling to risk a general war of islam versus the West.
3) The power structure is well aware that Americans value a strong economy over other factors, and a perception that we aren't safe anymore is likely to degrade economic activity.
Please note that I use the term "power structure", since this is not a matter of political party. It isn't just the politicians either - lots of voters and political contributers feel the same way. For that matter, very few would be willing to openly advocate the methods necessary to fight and win a general was against islam.
Now, as to the question of whether a lone individual can be a terrorist. Yes, absolutely. In fact, they make the best kind of terrorist, because that way there is no organization to pursue, no assets to seize, no comrades to compromise. It's called leaderless resistance. You can read a lot more about it HERE. (Note: Louis Beam is an ambassador at large for the Aryan Nations, and established a point system for assassination of federal officials. As such, his perspective may have some correlation with terrorist attitudes in general.)
This action was obviously planned! Send family back to Egypt - have TWO handguns and a knife (to kill and maim as many as possible) - Go to Israeli Airline counter where mostly Jews will be present - kill as many as possible before dying (as he undoubtedly knew that was what was going to happen there). Nutcase? "Beam me up Scotty!" - only as nutty as are all these barbarians that delight in murdering innocent and defenseless men, women and children.
The real question as has been asked is why our government tries to obfuscate the obvious truth. Neutrino has succinctly answered that for any who care to use their common sense.