a) I seriously don't understand why you would do the potato thing but also eat 1g/LBM protein per day. That's not the potato thing. That's just eating a lot of potatoes along with your usual food.
b) The point of the potato thing is that it restricts calories without leaving you hungry or totally devoid of nutrients. You're right, potatoes aren't magic, they just happen to be really good at making you feel full and also allowing you complete protein and a bunch of other nutrients. It wouldn't work with strawberries or twinkies or any of the other things mentioned because you'd get incredibly hungry and you wouldn't be getting adequate nutrition.
c) Plain old caloric restriction has a gigantic fail rate. Read literally any thread on these forums started by a woman. That's why we can safely call this a "hack" and not just a crash diet. There is a reason it works the way it does.
d) As Matthew Berry would say, get off your high horse. Chill out. It's just a fun diet hack experiment. Nobody is killing themselves. You're certainly allowed to think it sounds stupid, and get all condescending and Poindextery about it. And then we as a collective are allowed to tell you you're acting like a douche.