Anybody who ever served on active duty and handled classified information is just a bit hacked off at Her Majesty's cavalier attitude about, well, everything.
That's true, but comparing Hillary's sending and receiving emails that weren't marked as classified over a non-government server is absolutely NOTHING compared to Petraus' knowingly giving top secret information to someone with neither a need to know nor a security clearance. Remember Mata Hari? (I probably spelled that wrong)
Plus, his adultery is strictly against the USMJ code; people have gotten dishonorable discharges for that alone, and anyone else would have gotten time in Leavenworth for spilling secrets. Petraus got off not with a slap on the wrist, but a stern talking to.