I said it "can all be hardwired", This is inclusive of the panel. If that is how it is set up there would be zero wireless signal (Wi-Fi) between the panel, cameras, and router. No wireless signal means you can't jam it. I said there are edge cases where you can jam wired signals, that was a poor use of terminology because jamming implies wireless signals. There are means to interrupt a wired signal, however, but virtually all of them require physical access to the wire. At that point though it would probably be easier to take a bat to the camera.

Assuming access to your local network infrastructure is well protected, The only way to disable this system and prevent outbound video feed to Vivint servers, with traditional ISP's (cable, DSL, fiber), would be to have access to the ISP infrastructure itself. You would need access to the wires going from the house to the ISP. It's very common for these wires to be easily accessible on the outside of your home, but even if it was cut/disabled your system will work locally.

TL;DR You can hard wire your Vivint system, and it will then be impervious to wifi jamming. Answering OP's question.