It is true, either way, an unclassified network of whatever pedigree cannot be used to transmit classified information.
The point here is that this ‘woman’ intentionally set up, operated and HID a private network which did not come under the normal scrutiny unclassified DOS email would. NOR WOULD THERE BE ANY RECORD OF IT available to anyone except through HER or her lawyers (with plenty of time to slash and burn).
The very fact it was SHE who had the ability to delete emails of any flavor is the base reason she set up the network. To be able to erase incriminating evidence if she was found out. So, in my opinion, the “private server thing” is DEFINITELY NOT a red herring.
Agreed, it's definitely a problem.
My point was that the mishandling of classified data is probably thousands of times worse on the DOS system, simply due to the scale.