The election was not hacked, the DNC and John Podesta were

Washington Post:

U.S. takes action against Russia for election hacking

The measures include the sanctioning of agencies and individuals tied to the hacks and the removal of 35 Russian government officials from the United States. The administration's announcement culminates months of vigorous internal debate over whether and how to respond to Russia’s unprecedented election-year provocations, ranging from the hacks of the Democratic National Committee to the targeting of state electoral systems.

What the hacks of the DNC and John Podesta showed was the rigging of the Democrat primary for Hillary Clinton's benefit and the cynicism at the heart of her campaign.   The material that was presented was not "fake" and has not been really denied as truthful.  It is hardly worth a tit for tat expulsion episode.

What should be done is the US needs to get much better at defending itself against cyber attacks, especially ones that have much more potential harm to national security such as the Chicom OPM attack.  For that one "no Drama Obama" basically said "Thanks may I have another" and invited more such attacks by his passivity.  He also did nothing in 2014 when the Russians actually hacked the White House.

There is zero evidence that any votes were hacked.  By insisting on calling this event "election hacking" the media is presenting its own version of "fake news."  They are doing this to play into the narrative of Democrats who do not want to take responsibility for nominating a deeply flawed candidate who pushed unpopular policies and insulted voters.