Terrorists may call themselves as "Jihadists" but actually they're not. They may say that they do killing as it's Jihaad but actually it's not.
(What is Jihaad? In Islam)
Beware! They're trying to corrupt your minds and trying to change your thoughts about Peaceful Muslims, they aren't Muslims, cause it's said in Quran many times that If you have killed an innocent human being then it would mean that you have killed whole Human race, and if you have saved an innocent human being then it would mean that you have saved whole Human race.
Well Islam always said to attain peace and justice in all cases of life, whether we agree with it or not, it said it!
& if you don't follow the commandments of Allah SubhanTallah then it would simply mean that you're not Muslim.
So if someone calls itself as Muslim but don't follow Islam then it does mean that it's not Muslim.