Turkey has been the location of a number of crimes against humanity. The Armenian genocide in 1915 is a major event (that the government of Turkey still denies by the way). The denial of a Kurdish homeland (this also falls on Iraq and others in the area) is another issue. "Turk is for the Turks!" was the cry of the CPU (Young Turks) and now this state based on racist principles wants entry into the European Union. Should they get it? I don't know. It would help their economy (which I am for), but it would continue the oppression of the Kurds and give credence to denials of the holocaust against the Armenians.
There is no easy answer to any of this. Will fighting against these terrorist acts eventually cause them to end? That question can be broadened to ask... can violence end violence? I think Jesus gives us a harder, yet more successful way. Loving our enemies. Serving those who would seek to destroy us. Putting our needs and desires second to those of others (especially those who hate us). These are the ways that will, in the short run get you and me killed, but in the long run allow our children (or the generations after us for those who don't and won't have children) to have a better chance at lasting peace. Martin Luther King Jr., Ghandi, Jesus... all of these men knew that they needed to change people's hearts, not their actions, if there was to be real change. A gun will only change behavior for as long as the gun is loaded and pointed (which is why we will NEVER "win" in Iraq), but a changed heart has the potential for eternal change.
I hope Turkey realizes and admits its past mistakes, atrocities, oppressions, etc. and opens up opportunities for forgiveness and healing. Then the country can come together. Then, they will be ready to join the EU. This attack (though they don't know who perpetrated it yet) is just a symptom of the underlying issue of pride. Remember, God opposes the proud but gives grace to the humble. National pride is still pride.