Well Layla, likely because Trudeau doesn't practice the kind of divisive politics we've seen from others who are often the more reactionary types. I expect he believes, as other rational, intelligent, people do, that the attack is not only the barbaric murder of innocents but an asssult on the open, tolerant, pluralistic nation that is modern Canada. And that we, despite our differences, stand together against this kind of hate, intolerance, and savagery. 

In your case however, you're just trying to score partisan points. It's small yet sadly typical.