I hiked the PCT sobo in 2016 these are my reasons
Sobo's
1: Embrace being Non-conformists/non-traditionalist
2: Want the challenge of the "Harder Route"
3: Don't want the "Nobo/Big Bubble "Drama" (although had a fantastic small "drama-free" tramily from time to time)
4: Really Enjoy the Quiet Woods & Alone Time (didn't see another Thru on the trail for the last 2 months)
5: Loved the complexity of shorter days & learning how to adjust