Actually the rules on the handling of classified information apply to everyone, even Hillary Clinton. At least in theory they do. In practice almost no one is ever charged with the leaks, which is why they go on constantly, and federal employees, contractors and members of Congress toss around leaks like dinner rolls to serve their ideological or personal agendas.
When Attorney General Sessions announced a crackdown on leaks of classified information - reluctantly, and only after President Trump brow-tweeted him over it - it was treated as a radical and unprecedented move. Up until today, only one significant person - 25-year-old contractor Reality Leigh Winner - had been charged in the crackdown. No more. Now an FBI agent is going down, and his lawyers don't even deny that he did it: