Besides C programs, I can't really think of any other argument for the existence of C programmers. Most people these days tell newbies to learn a language like python, and not C, because, as newbies soon find out, C produces lots of memory leaks. The thing is, a lot of the good games, such as turn based strategy games such as Battle for Wesnoth (although that is written in C++) and Crossfire are written in C. Supposedly this was done several years ago when there were more C programmers, but I don't know anyone who writes C programs for fun, let alone for work.
Some people claim that C programmers must exist because of the programs, and think they hide in caves or in their basements and write code for fun. I don't believe it. I don't believe in supernatural nonsense like trolls either, because, if I did, I would be stupid, insane, or both. But that doesn't mater the point is a made up story about where C programmers are hiding out does not prove the existence of C programmers. Sure it doesn't refute it either, but that is meaningless without proof, a C programmer.