>>1083955While all of their videos are sponsored or have product placement to a certain extent, the first video you linked is literally an advertisement for Fizik. That guy talking is their product manager for fucks sake.
GCN wasn't telling you how to set up your saddle, that shitty company was trying to tell you to buy their overpriced seats so you can larp as a pro.
I wouldn't judge the entire GCN channel for one dumb advertisement. Most of their videos are full of extremely useful information. Here is where they are actually talking about bike fit, and they straight up say there isn't a "proper" way to fit your bike, but present you with useful tips that can help you find what works for you.
https://youtu.be/1VYhyppWTDc?t=13sI can understand you wanting to act like you are better than someone watching normie youtube videos from such a popular channel, but it might do you some good to be a little more open minded.