every religion has adherents who pervert it, like psychiatric patients who try to steal the truth and replace it with an alternate narrative. Describing a terrorist group as Islamic is like describing the Ku Klux Klan (KKK) as Christian. After all, KKK members use a cross and believe in Christ, yet they have persecuted and killed African-Americans in the name of religion and Christ.
Terrorists have various religions and political ideologies, and massacres have been committed in many countries with the aim of 'cleansing' those countries. There are people who claim the Jewish faith although their behaviour has nothing to do with Judaism, just as there are people who call themselves Hindus but whose actions actually have nothing to do with Hinduism. Bearing this in mind, claiming that terrorists are Islamic is preposterous.
