How have they defecated on it? The Democrats turned to the judiciary to ram through policies they could not win elections on. Roe V Wade being a prime example. Before that court, the Republicans made apolitical or non-partisan nominations. Roosevelt turned it into a political battleground when he was thwarted from imposing his regulatory nightmare of an agenda. And yet, Eisenhower & Nixon kept appointing moderates and swing votes, and the Democrats pushed ahead using civil rights as a cover for social experiments and engineering and ultimately overturning the legislative process in every state in Roe V Wade. So the Republicans HAD to start using ideology as a criterion for judicial appointees, to prevent the Democrats from simply suing for everything they wanted when they failed to win elections. EVERY swing vote on the court since the early 60s was appointed by a Republican. We didn't get a single one from Johnson, Carter, Clinton or Obama. Kennedy was stupid enough that White might very well have been a legitimate mistake on his part.

Assuming you are referring to the confirmation process, 2020 is not 2016. The president is not absolutely known to be leaving office, and he does not have an oppositional Senate. The position in 2016 was "let the people have their say" since there was an impasse between the President and the Senate. The most recent national elections had maintained the GOP control of the Senate, which is given the power by the Constitution to reject the President's nominees, a test the Democrats failed to meet in 2018. If they had retaken the Senate, they could block Trump's nominees all they wanted.

Garland is the first Supreme Court nomination by a Democrat since President Cleveland, over 120 years ago, to be rejected (and Cleveland's nominees were sabotaged by a Democratic rival). Did Garland get slandered and defamed in a Senate speech by a leader of the opposition party? Did he get his personal information disseminated to the general public? Was he subjected to trumped up accusations of dubious veracity that are impossible to disprove? He was not even subjected to a personal rejection, instead, it was made clear that the party was opposing the nomination as a matter of principle with regard to the president. He was no more entitled to a hearing than Kavanaugh was entitled to due process or a presumption of innocence. It says all you need to know about the respective tactics of the parties that Democrats are "entitled" to a hearing. For a Republican-nominated official the hearings are nightmares of defamation, false accusations and prying into their personal lives, in the case of Robert Bork, by such paragons of morality and intellect as Ted Kennedy and Joe Biden.