Every time Republicans win something everyone (Republicans, sure, but also media and Democrats) acts like they actually won in the sense that we think of it, i.e., as though they got the most votes, but Republicans haven't won the most votes in a national election in quite a while including 2016. This election more people voted for Democrats for: president, senate and house, and the only reason Republicans control all those things is the messed up system of electoral nonsense that exists in this country.
More people in this country wanted Clinton as president (or at least not Donald). More people in this country want Democrats to control the Senate and House. Democrats who are in those bodies need to act like they have the mandate of the people BECAUSE THEY FUCKING DO!
Republicans are good at winning election because they have learned and are willing to game the system (voter suppression, ballot initiatives, gerrymandering, appeal to lower population small states that hold disproportionate voting clout). Democrats, however, are--and have been for a while--the party that the majority of people in this country actually wants in power.
It would be really nice if the media would also do that but the media, despite perpetual noise about "liberal media bias" actually it actually gives far more credence/deference/respect to things Republican than to things Democratic.