Who are the FBI reporting to? Surely not to the president? Is it to Congress? Why wouldn't they just publish their conclusions?
Again, what sort of system is it that means the president, and the president alone, gets to ask the FBI to do this work?
The FBI is part of the executive branch of government. Ultimately, all members of the executive branch report to the president.
Congress may launch investigations of their own, but they wouldn't have the same authority.
As far as making the FBI report public, there are privacy concerns. They will be interviewing ordinary citizens whose only concern in this matter is that they knew Brett Kavanaugh in college. Not everything that went on in Yale dormitories ought to be a matter for public discussion.
I have wondered exactly what they will release, and how, and I really have no idea. They do not ordinarily reach conclusions as such. They usually gather data and present it to the decision making body, prosecutors or in this case the Judiciary Committee of the Senate.
My hunch is that they will make their interviews, summarize it in a report, and present both the report and the contents of the interviews in a confidential document provided to the committee. The committee will review the material and leak the juicy parts.
Here, anyone...literally anyone......can ask the police to investigate something, and it is then up to the police as to whether they do or don't.
It's pretty much the same here, but if the President says investigate something, they definitely will, and they can't just go around investigating people because they feel like it. Therefore, a presidential directive becomes both necessary and sufficient to launch an investigation of this sort.
And for all the sanctimonious blather going around about perjury, just as it was 20 years ago with Mr. Clinton, not every lie told under oath is perjury, and not every instance of perjury would be prosecuted. There are plenty of cases where acts that are, technically, crimes, but in reality no one is ever prosecuted for. (This is similar to mishandling classified documents. If everyone who mishandled classified matter were prosecuted, the jails would be overflowing with aerospace engineers, but in reality, most cases are not treated as crimes, despite what you might have heard in the last few years.)
If evidence were uncovered that showed Brett Kavanaugh lied about sexually assaulting women, I would not be surprised if he were impeached, and possibly even prosecuted after being removed from the bench. If Brett Kavanaugh lied about drinking, there is no way he would be convicted in the Senate, and if somehow the case ended up as a criminal prosecution, any conviction would be thrown out as an unconstitutional instance of politically motivated selective prosecution.
The sanctimony is strong in this case, but in reality no one would ever under any circumstances be prosecuted for lying about the meaning of "boof" in their high school yearbook.