That is not Kavanaugh's opinion, it is a constitutional principle that, on two occasions, led the DOJ Office of Legal Counsel to determine that a sitting president cannot be indicted for a crime. The POTUS IS NOT a private citizen, the only means to remove a POTUS from office is Impeachment, which is a political process, not a legal one.

The OLC reasoned that:

The indictment or criminal prosecution of a sitting President would unconstitutionally undermine the capacity of the executive branch to perform its constitutionally assigned functions.

Dept of Justice OLC Memorandum

There is no doubt that the democrat frenzy during this confirmation hearing is just one more l*****t schizoid freak show. Kavanaugh will be the next associate Justice on the Supreme Court.

It is all a moot point, but...a summation from Wikipedia:

The situation (following Garland's nomination) led to conflict between the White House and Republican leadership. Republican leaders claimed that the vacancy should not be filled until after the next president is elected, and threatened that the Republican-controlled Senate might delay the appointment of a new justice until after the inauguration of a new president. Republicans cited a 1992 speech by then-senator Joe Biden, arguing that if a Supreme Court seat became vacant during the summer, President Bush should wait until after the e******n to appoint a replacement, or else appoint a moderate acceptable to the then-Democratic Senate. Little-noticed at the time, Republicans began to refer to this idea as the "Biden rule". Biden responded that his position was, and remained, that the President and Congress should "work together to overcome partisan differences" regarding judicial nominations.

Democrats countered that the U.S. Constitution obligates the president and Senate to nominate and confirm a new Supreme Court justice in a timely manner, while Republicans explained how the Senate was fulfilling its obligation of advice, saying the next president should make the appointment. As there were 11 months remaining in President Obama's term at the time of Scalia's death, the Democrats argued that no precedent exists for such a lengthy delay, as previous presidents have nominated individuals in e******n years. Democrats also argued that even if such a precedent exists, President Obama's term had sufficient time remaining such that the precedent should not apply. The precedent, known as the Thurmond rule, dates back to the President Lyndon B. Johnson's 1968 nomination of Abe Fortas to the Supreme Court, and has been inconsistently applied.

Should there be a Senate recess of sufficient length, the president has constitutional authority to make a recess appointment of a new Supreme Court justice. Any justice so appointed would be eligible to remain on the Court until either the end of the subsequent Congress's first session, or until the Senate consents to a permanent replacement. Members of the Obama administration stated that President Obama did not have any plans to make a recess appointment.

On February 23, 2016, the 11 Republican members of the Senate Judiciary Committee signed a letter to Senate majority leader Mitch McConnell stating their intention to withhold consent on any nominee made by President Obama, and that no hearings would occur until after January 20, 2017, when the next president takes office. The 11 members are Committee Chair Chuck Grassley, Iowa; Orrin Hatch and Mike Lee, Utah; Jeff Sessions, Alabama; Lindsey Graham, South Carolina; John Cornyn and Ted Cruz, Texas; Jeff Flake, Arizona; David Vitter, Louisiana; David Perdue, Georgia; and Thom Tillis, North Carolina. By March 30, 29 Republicans had said they would not consider Judge Garland after the November e******n.

In an August 2016 speech in Kentucky, Senator McConnell said, "One of my proudest moments was when I looked Barack Obama in the eye and I said, 'Mr. President, you will not fill the Supreme Court vacancy.'"

There was no justifiable reason for not having given Merrick Garland a hearing after his nomination, either. One could argue the upcoming e******n is just as vital to making such a SCOTUS decision as it was in 2016. The treatment that both Garland received and Kavanaugh is receiving after their nominations were/are based on pure partisanship. Such politicization of SCOTUS nominee's and/or appointments will only end when one side or the other (God forbid both doing so ) quits playing partisan games.