He took up arms against the US and it's allies.
He was a key participant in the prison uprising that resulted in the death of a US agent (Mike Spann).
Washington and Jefferson certainly were treasonous in the eyes of the British. They knew they would likely be drawn and quartered if captured.
If you support the Taliban and al-Qadea you could make an argument to justify his actions but they are still treason.
Treason is the precise word for his actions.
The reason he was not tried or convicted of treason is the government did not want a complicated trial.