Yeah, I've discussed it in my prospect interviews and social interactions at junior tournaments with almost every forward I spoke to. And the answers and responses range from guys being very comfortable to do it (Berard, Kakko, Othmann, Holtz, Stützle, Cuylle, Edström, Höglander, Raymond) to guys who have a very outspoken preference to one side (Lafrenière, Ronning, Rueschhoff, Pajuniemi).
I have seen the same thing in other sports. Wingers in rugby are always very outspoken whether or not they can play the 11 and 14 positions or rather stick to just one spot.
You'd expect a 1st overall pick to have gotten used to that, but when you look at his trajectory throughout his childhood, he was always the best player on his team. So there was never a reason to play "out of position" and as such never got used to it.
Kreider had the same problem. He was always the best, most mature specimen on his teams, in HS-Prep, even in college and for national teams at different age groups. He was never asked to switch positions because he was often the first or second name on the line-up sheet.