I'm sure that's what they would like, but I used to work in that industry. Fabs are incredibly delicate and complex machines. Serious contamination of the DI water system or physical damage to the steppers that print the images on the wafers would be easy to do and very time consuming to fix. An embargo of fab equipment and repair parts would contribute to the fun. There is also a lot of nasty stuff around like miscellaneous acids and arsine gas. It wouldn't take very many insurgent fab engineers and techs to hose things up for a very long time.
I worked at a fab where a delivery truck dumped into the wrong tank and ended up creating a chlorine cloud. Fortunately everyone was evacuated safely, but the chlorine ate the copper traces off printed circuit boards in people's desks in a 3-story building. The fab had its own air system, but insurgents could also choose to fill the fab with chlorine gas. If that happened it might never again produce a circuit.