Not just the refs.
Both 'controversial' calls, stuck to the play called on the field, so the Chargers can't complain that the replay should have caught it. All that they can complain about is the rule deferring to the call on the field.
In the case of the first call, I personally do not think there was incontrovertible evidence for an overturn of the call on the field of an interception (both players displayed control, but one came away with it, and that was the call), but that does not matter. Because the equipment failed, and the fact that the rule defers to the call on the field in that case.
As for the empty hand, the ref called the play dead so Broncos could have given up on the play (I don't think they had a chance at the ball, but they don't write the rules for one situation, they write them for all situations). So again the rules deferred to the play on the field. And again the Chargers were a victim of the rules of the game, imperfect as they may be.