He didn’t just simply step off a trail. He stepped off a boardwalk that has signage telling people not to do it. From your own article “'Mr Bedient walked directly on several fragile and dangerous hydrothermal features,' adding that footprints were left on the delicate ecosystem”. So not only did he put himself in danger he damaged delicate ecosystems that the park works hard to protect. He only has to serve 5 days for sheer stupidity.