Fine, why have laws against littering, or smoking in public buildings, or jaywalking, or embezzlement? People are just going to do those things anyway, no matter what is written on paper.

We have laws to provide an enforcement mechanism for behavior that is unacceptable in our society. You’re right, in that laws written on paper can be ignored, but you do so at a risk of the penalties laid out in the law. Your argument essentially invalidates the purpose and effectiveness of every law. Clearly, we have laws and they work, so your argument is frivolous and empty.