It was definitely a clean hit in that it wasn't too high, a headshot etc...
The only thing that might be dirty about it is if the guy didn't have the puck. It's hard to tell for sure from any of the angles they show, but it looks like the puck isn't anywhere near him when he gets hit, in which case it should be an interference penalty.
The actual hit was clean, elbows down. The only thing that you couldn't really tell from in the video was when he got rid of the puck and how long after he was hit. If it is how it appears it should be an interference call, but it's hard to tell.
The hit itself was clean, but it's hard to tell from the replays how long before the hit Liivik had gotten rid of the puck. The slow motion makes it seem like a long time, so it seems like interference, but I'm not sure.
Why? That was nothing like the type of head hunting checks he through.
I think he is commenting on how it was solid body contact and the player getting hit looks like a rag doll. Scott Stevens threw plenty of hits along the boards, it's not like he only hit people in the trolley tracks.