Earlier quoted context omitted.
What do you mean office? The voters elect senators, who nominate candidates and then vote.
The President nominates and the Senate vets/confirms them. https://www.supremecourt.gov/about/faq_general.aspx
The senate judiciary committee will vote, then the candidate is voted on by the entire senate.
Regardless, the confirmation process is conducted by elected representatives. There is no "this party chose them".