Many very serious examples of security problems have absolutely nothing to do with software

Just because you can't fix all problems, does that mean we should try to fix any? You can also say seatbelts in cars are potentially dangerous. The buckle could fail to latch, causing a false sense of security. You could potentially strangle someone with the belt. Also, in some instances, the buckle might jam, causing the passenger to be trapped in a burning vehicle.

I don't see how E, CaPerl, etc could prevent this.

That's why links were provided, so you could study up! If nothing else, the next time this topic comes up, you'll be in a position to say "I've read some of the revalent literature and I don't agree, because...". That's a much stronger position to argue from instead of professing a failure of imagination.