This argument is so stupid.
Everyone is blaming the people responsible. That's a given. The reason people are blaming Israel and the US is because they are indirectly responsible since their actions are used as recruitment tools.
There are plenty of examples: http://www.businessinsider.com.au/the-manual-al-qaeda-and-no... http://www.cbsnews.com/videos/king-of-jordan-isis-used-gaza-...