I can think of several reasons for them to fudge on their public statements.
1. Actually labeling it a direct terror attack makes it one. Not labeling it as such removes the desired "terror" effect, so that life goes on as usual. Considering the small number of them, and the vast breadth of the U.S., such attacks really have no meaning unless they can spread panic -- why should the FBI do that on purpose?
2. Public profession of confusion may make the accomplices (if any) careless. This allows the FBI's real investigation to procede relatively unhindered, and in secret.
3. Labeling this as a terror attack requires a public response. This not only complicates the WOT (who do we attack?), but also requires a very high level of certainty if we did attack. Considering the costs of being wrong, the FBI is correct to check out these other options as well.
IMHO....
That is a good point. Statistically, one has a much greater chance of getting murdered by a run-of-the-mill homegrown thug trying to steal your car than one does a terrorist.
What is aggrevating though is the FBIs refusal to possibly consider the fact that this man simply hated Jews as a motive for his murder. They are trying to read some deep meaning into this when ther simply is not one.
When a raghead blows up Jewish children, no one looks for a "motive." This is no different.
The number one reason is CYA. The other reasons are valid, but so often public agenices distort or slant information to cover their screw ups or incompetance.