Speaking as a muslim, I do always condemn them.
Unfortunately, your logic is flawed, I live in North America, these people are killing muslims in their own countries. Those children that died when Taliban carried an attach on Peshawar school were all muslim's.
So its idiotic to think that these extremist will listen to me, who lives in Canada, shops in these malls and hell, condemn them every opportunity I get.
As a side note, heard an interview from a Taleban lunatic recently, you may not know, but he sounded like G.W.Bush, literally saying that you are either a Taleban or against them, which means you (me) a valid target.
So please, rest of muslim's are already with any other sane person and condemn them, vocally too. But you don't go out condemning every lunatic christian, nor will I, I have a 9-5 job, kids to look after. Medical appointments to meet and car to service. When was the last time you went to a street to protest, I never have, likely won't either. Those who understand this, I appreciate them, those who won't, I don't care.