“While not illegal behavior, it was disturbingly unmindful of the rules.”
No. The “rules” are not “rules”. They are laws, 18 USC. There is no parsing possible of this basic fact. Yes, I know that for the Clintons, rules are not rules and laws are not laws. They are just “friendly suggestions”.
And violating those laws requires concerted, deliberate, knowing effort to bypass systems & process in place to prevent violations. Secrets are on systems which cannot accidentally or easily transfer them to gratuitously insecure unauthorized systems.