He's just saying that if you write C in C++ it's as 'simple' as C itself.
> C++ is essentially C with a ton of features added on top.
You would just not use those 'ton of features on top'
Even unused code arguably adds to the overall complexity. But maybe that's what he meant, yeah.
Unused code adds to the complexity of a project you manage. However, you did not write the compiler: you are writing a program using the compiler. You don't have any unused code: you just have access to features you will choose not to use.