I don't think any of this is close to fair. "C is simple" and "it takes some work to do stuff in C sometimes" aren't mutually exclusive, in fact the former necessarily implies the latter. C is simple, which means it doesn't have a pre-written obscure built-in or convoluted syntax to handle every possible thing you might want to do in the language. You're going to have to write some of the code in your project yourself. That doesn't mean C isn't simple. I don't think I have to get into why writing a string-parsing function isn't quite the same thing as writing your own programming language.

And C has libraries too, to be fair. So if you prefer the "choose between 25 competing libraries that all provide the desired functionality but half of them are deprecated or don't work" workflow a lot of people are used to from C++ or whatever you can do that. Lots of people use libraries in C. In fact, as you might be aware, your OS's package manager doubles as the C language's third-party package manager. There has been plenty of "already-written C code," because it's a language that has been ubiquitous in computing for fifty years.

I'm not sure where these same tired critiques bubble up from but I see them constantly and they don't make sense. There are a number of entirely valid and damning critiques to be made of the C ecosystem but "there aren't any libraries written in C" and "oh, so you say C is simple, huh? Have you tried using it?!" aren't among them.

You're not going to be a 20 year veteran C developer and then suddenly just today learn about some obscure built-in, and that's what is meant by "simple" here, and that's a good thing.