Portability

The word “portability” is used to mean two subtly different things. People who say C is portable mean that the language itself is portable – if the platform can execute code, there is probably a C compiler for it. People who say Java, Python or Rust are portable mean that code written in these languages is easily portable – even large, complex codebases can just be copied over to another platform and compiled without trouble. Making platform-specific programs is opt-in.

C-style portability is nice because making software for bespoke platforms only requires knowledge of C. Java-style portability is nice because you can write code that works (and maybe even looks) the same for all of your users. Neither imply the other.