There really is no one who explains it clearly and simply. Trump never talks about it. If he does, it is really no more than an after thought.
People don't realize she let them die and there was plenty of time to rescue them and they did nothing.
Of course, the reason why they did is deeper and more revealing, that is, if we believe the explanation concerning running guns to ISIS. That has never gained traction, but is plausible.
Leaving those 4 to die without much of a thought disqualifies her for the presidency. I don’t think people really understand it - that it is just one of those things