I suppose it could be argued that losing democracy often results in significant loss of life and a reduction in everyone's quality of life.
Democracy is being lost when you start having low turnouts. When citizens lose interest in the matter of the state. When certain positions essentially always stay in the same family(ies). When there is zero confidence in the ability of the politicians to run the country. When it does not matter who you would vote, because the end result (for you) will always be the same.
Loss of democracy is a process, not an event.
At least Facebook, differently from "old school" mass media (granting for the sake of the argument that facebook is a mass media "entity") had no actual intent to push propaganda. It sold ads. To the wrong people? Maybe (granting for the sake of the argument that its selling ads to those people moved votes).
Democracy has been decaying from the start. It's decaying even faster now, but people putting the blame on facebook and the crazy guy that got elected president in the last round make me laugh. Sorry. :)