Outdated views. In this case the attack is much harder, because the offender has to:
1. Develop offensive AI capabilities in secret.
2. Procure hazardous materials (nuclear, biological, etc) illegally and in secret
3. Find funds for CPU. GPU, energy, etc for a rather large and hard to hide undertaking.
4. Deal with a whole lot of other players, both government and private, who are armed with AI and have a keen interest in anything looking out of normal or secret.
5. Lastly, the offender will have to overcome the AI-assisted defenses against his actions - you think defense is harder but you fail to notice that the resources used for defense dwarf those available to offenders.
With that said, some very large private makers of closed AI will still be capable of developing doom capabilities, this can be fixed by mandating open source AI and better antitrust regulations.
A few governments will be capable of developing highly destructive weapons too - as they're now, and have been for quite some time. This problem is independent of AI and requires smart policies like improving international relations, better treaties concerning WMDs, etc.