Doesn't anyone wonder what kind of training the Boy Scouts require? These jerks where on a Scout outing and did it in front of their charges. Anyone wonder what impression the boys have? The "rocking rock" may have been that way for hundreds of years, and easily could have stayed that way for hundreds more. The two putzes couldn't even rope the area off and contact the appropriate authorities, the park rangers and have them take care of their business.
Their less than juvenile behavior destroyed a formation that took nature hundreds of thousands of years to form. They took it upon themselves to destroy it and should be dealt with in a way equal to the crime. Some jail time in the county where it happened and a long time on probation with monitoring. Nothing says, I remember, than when you have to put criminal background on an application and automatically be disqualified from certain benefits.
The comparison to the works of art to me is appropriate. Only these are works of man, not the works of nature. Why should the penalty be any different?