It's very simple. Everyone has broken at least one of the commandments. They're the foundation of the whole law. If you break one of those, you're guilty. Period. People need to know what they're done wrong. Being saved makes no sense if you don't know what you're being saved from.
The other reason I posted them is that Christians need to know them. How do you know you're obeying him if you don't know what he said?