Why Is the Filibuster Only ‘Racist’ When Republicans Use It?

I get the idea of curses or bad karma. The house where a triple murder took place is going to sell for less than the one next door no matter how much you scrub the stains. I wouldn’t want to use Hannibal Lecter’s dishware no matter how much you cleaned it (and assuming he was a real person). That’s just some bad juju.
But what I don’t get is how something can be cursed, or evil, or otherwise tainted with eldritch energy—but only when certain people use it.
And yet, that’s precisely how Democrats talk about the Senate’s legislative filibuster.
Just in case you need a primer: The legislative filibuster is the procedural tool that lets senators, or groups of senators, speak for as long as they like on a proposed piece of legislation. This “endless debate” provision can only be overruled if three-fifths of the senators—60 out of 100—vote to invoke cloture, which cuts off the discussion. The result is that minority parties can effectively kill legislation that could actually pass with a simple majority but couldn’t get 60 votes.