Havoc != terror. Terrorists try to create fear and have a major impact on the populace, most often through bombings and death. Jamming a small (for now) part o

Havoc != terror. Terrorists try to create fear and have a major impact on the populace, most often through bombings and death. Jamming a small (for now) part of our communications infrastructure could be a major detriment to people functioning but no one will fear for their lives. That does not preclude, however, a Gotham city like scenario where an organization just makes a ton of stuff go wrong all at the same time. I agree with your first point because if you were to do a cursory glance at what could efficiently kill us in biology you would see how little effort is actually required. Anyone with a little knowledge could pull off a devastating attack using just DMSO and a few toxic compounds.