In total agreement with the anti "but what about..." statements.
If you want to talk about what Hillary did (or did not) do, that's fine. But it's entirely separate from what anyone else did. There is no equivalency. If you're accused of murdering someone, you don't get to point at Jeffrey Dahmer and say "but he murdered and ate people!". That's not a defense, it's a deflection.
In regards to Hillary Clinton, listen to Old Man -- I work in "security" as well. What she did in regards to a private email server wasn't great, but is NOTHING compared to what goes on daily at all levels of DC politics. Not deflection, just case in point of her actions being par for the course: do you think that Trump's cell (from which he constantly tweets) is secured? How about the email services of Pence, Ivanka, Jared Kushner, or other top-ranking officials? Think they're not using their own? It's a depressingly common occurrence....and not actionable (yet) without flagrant disregard for safety/security.