The investigation of Secretary Clinton's emails was damaging to her campaign. The FBI's exoneration did little to mitigate that damage.
None of this matters anymore except for Trump's unceremonious firing of former FBI Director Comey, for which ample evidence exists that it occurred because of the Russia investigation from Trump himself. Who believes Trunp cared about the FBI's investigation of Clinton's emails?
Why didn't Trump appoint a special prosecutor (which he can't do, but "Lock Her Up" is catchy) or push for her immediate prosecution instead of saying that she had suffered enough after he won the election?
And why the alt-right news push? This is pure spin because
Mueller has an earlier draft of Trump firing Former FBI Director Comey that his aides dissuaded Trump, for once, not to deliver. So the bs they are peddling is if Hillary was exonerated early by a letter, wasn't Trump right to fire Comey? Floating those balloons to muddy the impeachment waters.
White House Counsel McGahn inappropriately reviewed the earlier draft of the Comey firing letter. White House Counsel does not serve Trump personally, rather it serves the Office of the President.
McGahn has been subpoenaed by Mueller and now shares a lawyer with Reince Priebus.
As I've stated elsewhere, sometimes people need to have documents reviewed by others, like lawyers and other organizational members. They don't just scrawl them out to lie for their son on a plane while ignoring everyone's advice. Also, a draft of a letter not exonerating Secretary Clinton could also exist.
It's still irrelevant.
The FBI investigation was institutional, not performed solely by Former FBI Director Comey. He enjoyed widespread support from the agency before Trump fired him, but not enough to announce false results from an investigation regarding a Presidential candidate. There are people in government with integrity, and there were too many FBI agents and others involved for someone not to protest at a high level if Comey inappropriately exonerated Secretary Clinton.
Trump also stated on National TV while speaking to Lester Holt that he had already made the decision to fire Comey due to the Russia investigation prior to consulting anyone.
Trump also discussed Comey in the Oval Office whilst declassifying code word intelligence to the Russians that came from the Israelis to Russian Foreign Minister Lavrov and Russia's former ambassador to the US, Sergey Kislyak.
Trump called Comey "a nut job" and said that firing him had taken "great pressure" off him to the Russians.
Note: Kislyak's participation was not noted in the White House readout of the meeting. A Russian state photographer, the only media allowed in the meeting, posted shots of the smiling Trump and the Russians from the event on an official website.
Source 1
Source 2
Multiple additional sources available upon request
tl:dr: read the bold parts