Because you might be a gigantic toolbag, and the person with no or less PIC isn't?

Because they have a more well rounded resume, or their resume simply looks better aesthetically than yours?

Because they performed better on testing?

Because they might be better networked than you are, with more and better recommendation letters?

Because F you, that's why?

Aviation ain't FIFO, people. While favoritism certainly exists in this world, you get interviews and hired on your own merits, as decided by the company doing the hiring. That's not discrimination, that's life.