Who needs a plain old crime now? Crimes need endorsement, distribution, crowds.
You’re a small group with no reputation, and you start covertly blowing up or murdering the people of a big group, like a government or a nation-state or a whole race. And you can’t just do it and then go and do the next one. You have to do it, and then go and do your PR. “We just bombed your mall. It was us.”