Perhaps the reason is C is procedural, ie "do this, then this" -- In my opinion it's the easiest to start with, not complicated with overloading, classes, templates etc. I myself started to learn C++ but picked up C and stuck with it, learnt the C ways of doing things and haven't really used C++ since. However I'm considering getting back into C++.
I'm at the stage of doing the "Hello world!" exercises in C, C++, and Python. So far C seems to sticking better than the others (but that may change). So I'll pull on the Nomex undies and let youse guys tell me where I'm fouling up!