(1) I said that removing the C preprocessor is a stupid idea.
(2) I said that breaking C compatibility is a stupid idea.
These statements support each other quite well.
My point about "not having to use it" simply means that if you want to write code that doesn't use the preprocessor, you can already do that in C/C++ today. The fact that it exists is not forcing you to use it in new code. However, removing it forces you to not be able to use old code.
Hence, removing it has a measurable cost and no measurable gain.