She explicitly arranged a domain name, pointed to dnmx records to a server in her house so that she could evade state department oversight...In other words she removed herself from government authority. Good luck to Democrats that defend that.
I think in the end very few people will truly care about that.
But that's not the issue; evading government oversight as a public official is a grave transgression, regardless of whether or not she actually compromised national security. The fact that she took the risk of doing so demonstrates a serious lack of good judgement.