Just after 12 people were murdered at the headquarters of French satirical magazine Charlie Hebdo, my Facebook feed was an avalanche of grief.

Je Suis Charlie dominated my newsfeeds -- people expressed a profound sense of sadness of the unthinkable horror that played just after noon that afternoon on January 7.

"Imagine 12 people being killed in a left-wing publication in Canada," one friend said to me. "12 people shot at rabble. How would you feel about that?"

The answer is obvious. It would be a tragedy, just like the attack at Charlie Hebdo was a tragedy.

Thomas Friedman, the New York Times columnist, wants to see a million Muslims take to the streets to protest against "the scores of Muslims recently murdered by jihadists in Pakistan, Yemen, Iraq, Libya, Nigeria and Syria." Well, I fear it's more likely thousands than scores, and this very list could easily reinforce some pretty ugly stereotypes about all Muslims. But those stereotypes would be false. In truth, despite the terrifying sporadic attacks and the lurid media coverage, we in the west have little to fear from violent extremists.

When I was in journalism school, a professor offered me a valuable piece of advice: "Half of the struggle of being a good columnist is choosing the best target."

It's a useful reminder for leftists too. We have to be intentional and intelligent when choosing in which struggles to engage. We have finite resources and time. Our choices are  political acts in and of themselves.

I suspect there was a huge swath of progressives these past two weeks who didn't agree with the amount of attention given to the murders at Charlie Hebdo by other leftists. Surely, as many have pointed out, the Charlie Hebdo murders shouldn't overshadow the murder of thousands in Nigeria, for example.