No, you're still not getting it. It isn't about inefficient abstractions. C++ has lots of zero-cost abstractions, but that's not what the parent is talking about.

He's saying that C is simple because it offers a small set of mostly orthogonal features. You get structs, functions, pointers and integers, basically. You don't even have opaque 'String' types or any of that. It's all simple, orthogonal bits.

In C, if there are no macros involved, everything you read in code is arithmetic, function calls or pointer dereferencing. There is no overloading, there are no automatic secret implicit constructors, there are no destructors, no garbage collection, etc.

C++ has a huge amount of behaviour, a lot of it very abstract compared to C. For example, vtables. How are they implemented? That isn't clear at all from reading C++ code. You have to go look at the generated code. If there are vtables in C you have explicitly written

    struct vtable {
            foo_function *foo;
            bar_function *bar; };
    struct a {
            struct vtable vt;
            ...
    };