It is not difficult. Really, it’s not.
The difference between Hillary Clinton and David Petraeus, or Hillary Clinton and Chelsea Manning, or Hillary Clinton and Edward Snowden, is…
She did not knowingly and deliberately give classified information to people who had no right to it. Petraeus gave classified material to his mistress, Manning and Snowden gave classified material to WikiLeaks. Maybe you think that they acted in the best interests of the country (Manning or Snowden, anyway), but that’s irrelevant to any discussion about Clinton.
I don’t care if you are a conservative fulminating because she was not indicted or a leftist aggrieved because you wanted her to be eliminated as the Democratic nominee, or if you’re Edward Snowden pretending that setting up that email server was the equivalent of dumping mounds of classified materials in Julian Assange’s lap. The law requires more than “I don’t trust her.”
You want to argue “gross negligence”? That’s another bag of marbles, and maybe — or maybe not — you have a point. James Comey didn’t think so. And the man served under GWB as well as Obama, and before his actual announcement was lauded by the Republicans in Congress as being the soul of integrity. They only decided he was hopelessly corrupt when he declined to do what they wanted.
In any case, don’t bring in Snowden, Manning or Petraeus. Pretending as though what she did was equivalent to what they did simply makes you look foolish.