What the heck does a mere opinion accomplish when written into the law?
It is actually common. The findings provide an understanding of the "legislative intent" of a law. The clearer that intent, the less wiggle room there is for judicial interpretation of the law.
I knew that and was expecting this. "Intent" is also in the Congressional Record, where the debate does more to define intent than such a section ever could. It doesn't have to be in the law and shouldn't.
I care not a whit what is usual or customary among the gang of posturing amateurs we call Congress. Laws should be simple, changes should be rare and few. The easy way to accomplish that is to stay within the confines of the Constitution. Were that the case they might even read the drafts before they vote.