Not that I am defending them, but if you enlarge video they are teenagers. Teenagers do stupid things. I think what ever it cost the rocks should be put back, and they pay for it.
If they were my kids, I'd beat them half to death with one of the rocks. I'd fight like a momma tiger for them, but I would reserve the right to smack them up side of their stupid heads.
Bay my mother would have done the same. Half the group is male half female. Bet teenage boys tiring to impress girls with their strength. No thought given pass impress girls.