Most of the angry people don't seem to realize or forget that laws need to be upheld to protect the innocent from being punished unjustly. Yes sometimes guilty people go free on technicalities but those technicalities are also there to protect innocent people from unjust treatment. I suspect most of the people that understand this but are still against this settlement are people that come from a place of significant entitlement like Ms. Wente. Anyone who is law-abiding but knows of or has experienced unjust treatment by the government due to socio-economic, race, sex or other factors would rather have some guilty go free (as terrible as this sounds) if it means that the innocent don't have to fear populist or mob justice dealt out by those that will never know such discrimination. 
Khadr should have faced Canadian justice in Canada immediately after he was caught end of story. Do you trust the US intelligence to get the facts right about "combatants" all the time? I sure as heck don't.