The C language is one of the "simplest" languages out there. Purely in terms of *language*, Python or Javascript are much more complex.
Then you say,C is simple, but needs significant boilerplate code for even simple stuff. Say you want to handle dynamic lists of objects; it's very easy in Python, while in C, you need to master a number of concepts.
This appears as a contradiction, on the one hand, c is simple then on the other, you say... 'its very easy in python, whilst c you need extended knowledge and much more code overhead.
It is absolutely not, and your reaction actually shows the crux of the matter! C is a simple language, and as such, doesn't have many built-in features, which often makes it hard for beginners.
Python has a lot more features built in the language, which objectively makes it a more complex language.
A simple language doesn't imply it is simple to use. And, we would also need to define what "simple to use" exactly means. If easy means, as is often the case for a beginner, that you can quickly achieve a given result with the language without having to spend months learning it, then surely Python and the like are simple to use. Now if it means, very readable and easy to maintain, that's yet another matter.
If you want to understand what "simple" means for a programming language, I suggest reading Niklaus Wirth (which, incidentally, has had ideas of even simpler languages than C.)
To better understand the point, knowing all of C is absolutely possible once you have properly learned it, and the knowledge will linger on - that explains brucehoult's comment. I dare you to know all of Python, even after years of use. Even a seasoned Python programmer will probably have to open a book, search Google or spend time on Stackoverflow (or the like) on a regular basis. Probably the younger generation finds this appropriate and "easy", but that's only from a restricted point of view. That makes you dependent, whereas with simpler languages, in the sense I explained, you can be fully autonomous.
Many beginners these days don't care about becoming autonomous, or learning things that they'll still remember in decades, they just want to achieve things.