It's just out of respect. You just don't steal any ideas without asking. I learned a lot from Magner. I looked up to his work. I didn't just steal everything he did, I first asked if I could use some of his ideas or if he could share some. And he really helped me with giving some personal advice.
I don't feel like I'm a pro like Magner is. Ofc not. I just started with photoshop. It's just sad he just steals the ideas without asking if he could expand it.