The main motivation for their activities does not appear to be Germany’s contribution to ISAF, but their general contempt for Western societies in general and German society in particular. The reason for the increased number of threats seems to be the militants’ accurate perception that German society is easy to intimidate.

– Fritz Gelowicz (IJU) stated that German “potatoes” (“Potato” is an racially abusive term used by migrants with a middle eastern background for ethnic Germans. The term refers to the blonde hair colour of many Germans.) will be “hit in the face”. He called Germans “cowards” and “uncool”.
– Adem Yilmaz (IJU) stated that he hates Germans, who are “without character” and would not even defend their girlfriends.
– Members of the “Sauerland Cell” (IJU) stated that they wanted to kill “American sluts”.
– Youssef El Haj Dib (who participated in the failed attack on regional trains in 2006) stated that he had “problems with German lifestyle”.
– Jihad Hamad (El Haj Dib’s accomplice) stated billboards advertising underwear for women as the initial reason for his contempt for Germans.
– Ata Abdoulaziz Rashid, Rafik Mohamad Yousef and Mazen al-Hussein (who attempted to kill Iraqi Prime Minsiter Allawi during a visit to Berlin in 2004) repeatedly tried to humiliate the female judge who oversaw their trial. They called the judge a “cheap little slut” and generally did not accept her authority because she was a woman.
– Bekkay Harrach (Al-Qaida) mocked German security agencies who interviewed him repeatedly but did not have the authority to arrest him.
– Eric Breininger (who is currently in Pakistan or Afghanistan and appeared on several IJU videos) appears to be motivated by the recognition his fellow militants give him.

Some of the sources for these statements can be found here: http://weblog-sicherheitspolitik.info/?p=1542.