I take dianavan as saying that not all terrorist groups are motivated by religion, but in many cases by nationalism related to foreign occupation, which is pretty evidently true; rather than that that all terrorist groups are motivated by nationalism related to foreign occupation, which is pretty evidently not true. (Her wording is ambiguous - a "many" or "generally" after that "but" would make it clearer, if my reading is correct.)

Though in fact, of the examples Wolfgang gave, many Pakistanis would regard the partition of Kashmir as constituting a foreign occupation of part of their country, and this has been a very significant element in the development of terrorist activities.