Unlike people who got lesser punishments, Pollard was helping a friendly country, not an enemy. Americans who actively supported the enemy in WWII were often let out. CIA and FBI agents who helped enemy states received more leniency. And, Tenant only got the medal so that he would keep his mouth shut about how badly he and the Whitehouse people screwed things up. Apparently the money he got in the book deal helped him open his mouth back up.
In Bahrain, 2 police officers killed, 6 wounded in bombing (AP)
from the article: Ex-CIA director: I prevented move to release spy for Israel