The Rangers were, probably, the only team having Lias rated that high. They drafted him way out of position. Maybe they thought they were outsmarting everyone, but watching the kid play, I can't see what it was that made them think he was worthy of drafting with their first pick.
On the other hand, CM was always regarded as a top 10 talent. His skating and skill are evident, even at this young age. Maybe Lias will prove me wrong, but I haven't seen anything in his game that would lead me to believe he is anything more than a 3/4 C. That's not good enough for 7th overall.