Some players play with an edge; which side of that edge they fall on is up to them. There’s nothing wrong with setting the tempo with a big hit or aggressive pressure. In fact, I’d argue in its favor (and I would like to see the Blues do it more against Colorado).
A big hit can turn into a problem when the player making that hit, someone who has played hockey his entire life, makes a conscious decision to turn that big hit into an illegal check. Nazem Kadri does that fairly often. He has been suspended five times in his NHL career, most recently in the 2019 playoffs for a vicious cross-check on the Bruins’ Jake DeBrusk.