Earlier quoted context omitted.
Credit reporting agencies have immunity from slander claims unless you can prove malice.
So you've found the problem. If they are immune from the crime, they won't stop practicing it.
It's merely a tort (wrong). It never rises to the level of a crime. The few instances/places where slander is a crime in the US (historically or otherwise) are very problematic and subject to abuse.
Perhaps this specific kind of slander should be criminal, but it might be the only kind that should be. Not only would you need to justify that philosophically, but somehow convince legislators to make it that way (at the federal level, I should think).
It'd be a tough journey.