Your claim that the handling of top secret information is only guidance (not a law), says a lot more than I need to say.
There are numerous criminal codes covering these matters.
Simple. Her underlings typed most of the emails, and even if they were transcribing from a terminal showing top secret emails (many were allowed to have secure and unsecure terminals side-by-side) they would certainly not type the top secret markings into the email they sent to Hillary. That makes them criminals, but like I said, they all got immunity. By the time she got the emails there were no more top secret markings, only a few Confidential markings ("C") that slipped through their revisions.
There was no law disallowing the use of her private server and private email for unclassified business, but she clearly violated policy. She also violated the law by using the same system for top secret information. But again, I ask you, where is the evidence? The State Dept went through the emails from the server and said some were top secret. Her reply was that was "after the fact' classification. She also had ample opportunity to delete classified emails including any marked as classified in the 30,000 or so that she claims were about "yoga" or the wedding of her daughter.
We all know that is BS, doesn't pass the sniff test. But prosecution requires evidence and evidence comes from investigation. Obama's FBI did no serious investigation and we can guess from the biases of the investigators that they probably destroyed evidence.
The rule of law requires investigations, evidence, indictments and trials. I would love to see her indicted today, but that would not be the rule of law.