This is a remarkably common belief and it bugs me to no end. I don't know why, but many people have developed this conviction that C is required for computers to work, that that's the baseline of computation. This comes from both novices and experts. I haven't figured it out.
The C Abstract Machine looks like a generic machine based on the Von Neumann architecture, so it "feels" like it should be fundamental. Add in some sunk-cost fallacy, and a lot of people end up with the belief that C is fundamental to computing, despite the existence of systems that do not use any C.