Sure you do. Unless you're omniscient. In which case, I say "gimme gimme".
In my opinion, what he did was grossly immoral and reprehensible. But, maybe there's something I don't know, or some factor I don't see. G-d is omniscient and perfectly just, so his ruling is going to be correct. Mine is fallible. The laws of G-d are different than the laws of man. I am but a man, so all I can give is my opinion, not a conclusive decision.
The man was a spy and deserved severe punishment under the code of law. End of story.
"But, maybe there's something I don't know, or some factor I don't see"
Slippery slope, my friend. One could say the same thing in praise of the devil himself, which in the case of Pollard, probably is the most apt comparison.
There is no confusion. His acts were treasonous, and immoral. He should have been executed for them, but it wasn't my call.