If the Russians did tamper with the election, the citizens of the U.S. need to know what happened.
If the tampering was limited to hacking into the Democratic National Committee computers, and releasing what they found to the public, the the outcome of the election should not be called into question. There are many news related factors that affect the election, and false statements were made by the candidates and others. What was released about the DNC was true.
On the other hand, if the Russians did anything to affect the counting of the votes, that would and should cause us to call the results into question.