

To clarify, “Stockholm syndrome” was coined in regard to a woman who was held hostage by bank robbers in Sweden. When interviewed later, the woman recounted that neither the police nor the mayor seemed concerned with her safety, so she buddied up with the robbers to maximize her chances of survival.
There’s a second factor at work, which is that the institutions targeted by more “extreme” actions also don’t want those actions publicized.
Consider an action like the one depicted in “How to Blow Up a Pipeline.” If they don’t have a perpetrator in cuffs, the oil company and the cops would not want to admit the action happened at all, because it makes them look vulnerable.