Why do settled immigrants commit terrorist acts against countries that have accepted them? Preliminary remarks

Some people behind terrorist attacks committed in the 21st century in Europe include immigrants or descendants of immigrants, which is abominable to the native population. In this paper, I analyse factors that account not only for cultural or political motivation of the terrorists, but also factors conditioned by interaction between immigrants or their descendants with indigenous people of the host country. One of the fundamental questions to be asked is whether immigrants in European countries are really accepted by residents of the host country. If they are indeed not accepted, they might have developed a sense of exclusion, even despite achieving apparent integration at certain levels of the social structure. The sense of being rejected is a major factor causing aggression, and such aggression can be used by terrorist organisations to recruit such people.