Unfortunately, it all boils down to money. I am a lod retired leo, and the federal court system can be a nightmare. I am not sure what jurisdiction these charges were filed in, but I am assuming in a federal court. If that was the case, the federal judges can get pretty pissy about what comes up on their docket. Once again with out seeing the charging documents, I am fairly sure that they we charged with a federal misdemeanor.
If that was the case, it would have been cost prohibitive to hammer that family by going to a court trial. First, the prosecution runs the risk of pissing off the judge, because he may see as a waste of his time. Secondly, the federal prosecutors are no slouches and are very detailed in their work. They are actually graded on their win/loss ratio. So, they will spend whatever amount of time that is necessary to secure a conviction. You also need to look at the Ussc sentencing guidelines.
The maximum sentence for a class a misdemeanor is 1 year. It cost roughly $100 per day for incarceration. Then who goes to jail? Daddy or Mommy or both. If you send the breadwinner of the family to to jail, who suffers? The kids most likely. Sure, you could impose a heavy fine, but you are going to destroy a family for pooping on the beach.
Look at the outcome of this case. The family had to literally clean up their poop, under the supervision of the nps. They learned their lesson. They park will recover environmentally. For that family justice was served. The press could have covered it and sent a great message as a deterrent, but they might not to have wanted to publicly humiliate the family. I learned a long time ago that stiff penalties are not a deterrent, but active enforcement is. Where is lorax when we really need him? You can look at yellowstone. They actively prosecute individuals for walking out on the geysers. Even with active enforcement, folks continue to do it.
I know it sucks how people treat our beautiful lands. It seems that most have no respect for nature or the fact that what they destroy may never recover or it may hundreds of years to. Our national parks are being loved to death, unfortunately. There might be someone on this site with a jd or experience with the federal court system that has jurisdiction over Lake Powell that can flesh out this perspective. All of my experience, is with the federal court in Denver.
I hope this provides a little different perspective on the punishment that the pooper family received. Just think what lake Powell would look like without those great volunteers who drive around the lake on their time and pick up others peoples garbage.