It’s their very own rule book

From the US Senate Judiciary Committee:

When a vacancy occurs on the Supreme Court, the President of the United States is given the authority, under Article II of the United States Constitution, to nominate a person to fill the vacancy.  The nomination is referred to the United States Senate, where the Senate Judiciary Committee holds a hearing where the nominee provides testimony and responds to questions from members of the panel.  Traditionally, the Committee refers the nomination to the full Senate for consideration.

I don’t see anything there stipulating exceptions for a boycott or a sitdown strike or a refusal or a right to take a year-long vacation first. I don’t see any “unless the Committee or the Senate doesn’t want to.”