Your basic argument in that post was "we pass laws to give legal recourse," so I'll address that directly.
Our legal system is incredibly complex, and as such, there are many different reasons and purposes for every law we pass. One of those purposes is to provide legal recourse for law enforcement.
Another purpose for creating laws is to stop a particular behavior from occurring. We have federal pseudoephedrine laws. The purpose of these laws is two fold. One, to provide legal recourse when drug stores don't follow the law. And two, to prevent consumers from buying a bunch of medicine and turning it into crystal meth; to prevent a behavior from occurring.
We also have cigarette and alcohol laws, regulating who can buy both substances. Again, the purpose of the law is two-fold. To provide legal recourse, but also to prevent a behavior; minors buying cigarettes.
If you think that laws only have one purpose, then you're wrong. Background check laws, like all laws, have many purposes, and preventing a certain behavior is absolutely one of their goals. And it just so happens that background checks are incredibly effective at preventing a certain type of behavior, and rather ineffective at providing legal recourse.