I don't know if I'd call it him naturally being passive. I don't think he tries to play passively. He just doesn't think the game well enough to put himself in the right spots to be anything but passive. When you are constantly out of position and incapable of reading defenses, you will look passive because you are thinking the game two steps behind everyone else. It's the same reason people think he's a bad skater. He's not a bad skater (he's about average), but because he's constantly out of position, he never gets to effectively use his skating.
I hate to bring up some bad apples, but there's a pretty bad trend of players who get drafted really high solely because of their shot turning into, at the bare minimum, dissappointments. Kieffer Bellows, Owen Tippett, Oliver Wahlstrom, Alex Holtz. The guys who haven't had infinitely better all around games and have translated extremely well, namely Cole Caufield and Jack Quinn. Both of those players not only arguably had the best shots in the draft, but had quick releases and could score in a variety of ways. They were the best goal scorers. It is way more important to be a good goal scorer than a good shooter. Being a good shooter means nothing unless you really know how to use your shot. It's easy to light it up in Juniors having a crazy shot because you will naturally have more lanes open up because of worse defense and easier goalies to score on. Doesn't really help with developing that game sense for creating shots for yourself at a higher level.