C programmers don't install dependencies. That would be insane. Better to "vendor" them into the same tree as everything else and build them at the same time.
If dependency == library, it is hard in C or Python, but it isn’t in Rust or Java.
You could easily run a Rust program on bare Linux, but using Docker might simplify the version management story.
But even if you use a language with a sane dependency management story, you probably depend on PostgreSQL, and running it in Docker can be easier than installing it on the system (since distros really like to mess with the PostgreSQL configuration).
