Treason requires intent to betray the nation. It's no mystery that a lot of otherwise intelligent people believe Clinton, and Obama, actually all Dems, are out to destroy America. Actually, throw in everyone who doesn't own 3 guns, or speaks with an accent, or wears strange clothing. They're all traitors before they actually do anything.
That doesn't change that by law, there needs to be some indication of a deliberate act of betrayal to warrant charges of treason. What Clinton did is equivalent to leaving her car unlocked when she ran into a store to buy some milk, when she had some secret documents inside. Poor judgement. Not treason.
Next time that same person tells you anything, keep this in mind.