It's not heartless, but I think if it's breeding cynicism in you, that's something to check yourself on. There's nothing wrong with holding vigils for people in the community that have been lost. Hopefully this doesn't come across as heartless either, but I can understand it because those people were part of the local community whereas those who are in Iraq are not. Still, though, the idea of having a vigil for them is a cool one.
That being said, you clearly have a lot of passion and heartache for what's been happening there. One really cool way to channel that positively would be to have a prayer vigil. Have you thought about organizing one in your city? That would be a really cool and relatively simple thing to do I feel like, and it would be a way you could directly address this problem you've observed with the persecution of Christians in Iraq not being acknowledged enough. Just a thought