“Politics should not be part of the selection process.”
I think the operative word there is “should”. But like it or not, it is.
Your comparison of the Clarence Thomas and Merrick Garland situations is interesting. Clarence Thomas was considered, given a hearing, and a vote was held. By a Democratic-controlled Senate. None of those things was done for Merrick Garland by a Republican-controlled Senate. The two situations are not comparable.
As far as “dirty politics” by the Senate during the Thomas hearings, you’ll have to provide an example. I am aware of a leaked FBI memo concerning complaints by Anita Hill that was leaked to NPR by an unknown party, but I’m not aware of any “dirty politics” coming from the Senate.