And WHY is this sorry excuse for a "soldier" not doing his time at Guantanamo with all the other jihadist terrorist scum?
Why is this traitorous, born-again muslim scum still kicking?
Because he's a native born US Citizen, entitled to a trial. Fortunately military trials (courts martial) are not, in general, lengthy. Nor is the appeals process. The militay has it's own, "Court of Appeals". The only place the military justice system intersects with the civilian one is at the Supreme Court. They, including the military judges, want to be sure all the i's are dotted and the t's crossed when and if the case gets there.
They don't need that testimony to get a conviction, so throwing it out eliminates one possible ground for an appeal.