We have established that ignorance of the law is not a defense.Mens rea
is not even close to ignorance of the law. An unmet mens rea burden doesn't happen because you didn't know murder was illegal but because there exists insufficient evidence to establish that you acted without the knowledge or understanding that your actions were going to kill someone.
A quick Google search will show you that Clinton was investigated under certain numbered sections of the US Civil Code. The good thing about criminal laws is that they almost always outline the exact planks you need to meet to determine guilt- you can find those fast by searching through the US Civil Code and peeking at relevant case law. (If you want, there's also a few detailed legal analyses of the investigation that you can find, I must note among which the conclusion is apparently universal that there was insufficient evidence to level any charges.) You'll find that the published/known evidence falls incredibly short of meeting the burden to the point that- as the FBI had worded it- "no reasonable prosecutor" would pursue this case.
If you think that at any point it was established that "Clinton broke the law but got away with it" or that Comey defended her in some way, I recommend going back and looking at the actual publications by the FBI, the known evidence, and comparing them with the law. While it was widely reported by certain outlets (CNN comes to mind) that Clinton broke the law, that goes in direct contradiction with the fact on the ground and the facts in the report.
There's not a whole lot of nuance here, really just public illiteracy when it comes to the law. But that's no surprise; 3 out of 2 people are retarded, and that goes double for this site.