This is a stunt by Green Hills Software, a maker of embedded operating systems and programming tools that supplies directly to Tesla's competitors (and stands to lose massively as Tesla grows). You might be interested to know that they initiated a public relations campaign decrying the use of Linux as insecure back in 2004:
https://lwn.net/Articles/83242/
Here's an article by the very same Dan O’Dowd: "Linux: unfit for national security?"
https://web.archive.org/web/20040912190752/http://www.ghs.co...
https://web.archive.org/web/20040916074333/https://www.ghs.c...
https://en.wikipedia.org/wiki/Green_Hills_Software