That means don't condemn others. It does not mean "don't bother cleaning up your own act". It doesn't even mean "don't make moral judgments about what other people do".
No, that means everybody is a "sinner". It can be argued that anyone who writes closed-source software is unethical (see Stallman et al). But open source programmers are themselves unethical, being privileged enough to give away their work for free which drives down salaries of less fortunate coders. There's simply no programmer who can be described as completely ethical, and your helloworld.c is the Original Sin.