With respect in return, it's yourself that's glossing over the crucial differences.

- Arar was a man. Khadr was a child.
- Arar spent less than a year in prison. Khadr spent over 14 years in prison for a crime he may not have committed, and for which he would never be convicted under the Canadian justice system.
- Canadian officials directly abused Khadr's rights. None did so in the case of Arar.
- The Canadian government didn't block the repatriation of Arar. It did so in Khadr's case.
- Besides violating Khadr's rights under the Charter, the Canadian government violated it's obligations to Khadr under the convention on child soldiers.

Arar's detention was not a direct result of Canada's actions. Surely you're not saying that the Canadian government asked the US to send Arar to a Syrian prison for torture? What happened is that, acting in good faith, the RCMP gave erroneous information to the US. After that the US acted on its own.