I'm pretty certain the question is trolling, but... It's because sitting in front of a computer coding all day, everyday makes a person fat and boring. And no

I'm pretty certain the question is trolling, but... It's because sitting in front of a computer coding all day, everyday makes a person fat and boring. And nobody else wants to hang around people who are fat and boring. It may not be obvious that coding all the time makes a person fat and boring, so the "get out and do stuff" responses are warnings to let people know that there's more to life than writing code.