........They consider "Islamists" as the only evil element in this world, ......
Well it will help you to keep things in the context. If we were talking about some parts of Africa then terrorist evil may be Hutus or may be Tutsis.
In the context of Somalian pirates, the terrorism may be just Somalis.
In the context of Sri Lanka, the terrorist evil may be Tamils.
In the context of UK, 7/7 bombers or self burning doctors of Glasgow were Islamists. But if you go back a while you may find Irish variety too.
But in the context of "this thread", the terrorists did come from a particular religion. Hope you can understand this basic logic aka logic 101 scenario.