While I can understand where they are coming from, your post is spot on. They are blaming the victims instead of the perpetrators.
Otherwise we will end up blaming the Amish for the murder of their children ("how dare those Amish live a counter-cultural life in America, it just attracts the crazies"). Or blaming the Iraqis for the death of their children in suicide attacks("they should have kept them away from Americans giving out sweets - that's just reckless endangerment")
We must put the blame where it belongs: on Islam. Otherwise we will lose.