be of interest...the vast majority of emails in question were deemed 'Confidential' AFTER the fact...only the three that are mentioned were established beforehand.
They were not "Top Secret" withdrawals like those that Trump took, but the lowest level of security i.e. 'Confidential'...two of them were judged to have markings that could easily be overlooked by HC (see link) and the third could not be verified...that's how "BAD" it was...or in your terms...a "Nothingburger"....yet Trump and the GOP wanted her "Locked Up"...
Trump's stealing of many "Top Secret" documents and refusing to return them is in a completely different league...if HC should be locked up, then what have you to say about Trump's culpability?
Link: https://www.factcheck.org/2016/07/revisiting-clinton-and-classified-information/