You either haven't looked at how cxx works, or you're intentionally misrepresenting it.

cxx generates code that uses `unsafe` blocks/functions. It then generates safe wrappers around those, which are what it exposes to users. It's no different then someone doing this:

  pub fn safe_fn() {
    extern { fn unsafe_fn(); }
    unsafe { unsafe_fn(); }
  }

cxx just uses macros to generate that. You're welcome to have a different opinion on whether or not the user must pass an `unsafe` token to the macro. But that has no bearing on the code generated by the macro.

Statements like "Party A wanting safe Rust to have undefined behavior was wrong" are just straight up incorrect.