"But Jensen didn't skate himself into the boards", You're really just playing dumb, aren't you?
Essyimont has no way of knowing Jensen is going to take all of his weight off his left leg for a dump in and stare, he has no way of knowing Jensen is defenseless and vulnerable and going to be flattened like a pancake, he's finishing his check at an angle that shouldn't result in that outcome. He's not near the boards, he's giving up ~30 lbs to Jensen, he's hitting him from the front/side and on the shoulder, he's hitting him within like a second of the dump in, none of this screams dangerous.
Do you really not see the difference between that and a player pinned along the boards and vulnerable? There's a reason refs have stopped calling penalities when a player turns their back at the last minute along the boards and putting themselves in a dangerous position, there is a responsibility to the one being checked to avoid being vulnerable, where as if you're already along the boards in a bad position you have no choice. This is where I understand why Jensens dumped and stared, he's not in a part of the ice that is dangerous, or so he thought.
It's just unfortunate
A.) Jensen is at the end of that motion, Eyssimont knows he's not in a position to take contact very well. That's
why he's selling out to finish the hit, for a bigger result. Even taking the motion out of it, we've all seen enough hockey to know that he's chasing down a guy who is going to get rid of the puck as soon as he gains the red line and does. This isn't a threat, it's a guy he's going to try to finish by the letter of the law but doesn't need to worry about at all. You're
right that nothing about the play screams dangerous.... except the follow through.
B.) It's exactly because of his angle and that pretty unnecessary follow through that he tossed a guy all the way into the boards, which can and should be argued as a boarding call. How
near you are to the boards is not a part of the language of the rule, it's a matter of if the hit causes the opponent to violently and dangerously impact them. So when you elect for the big finish you need to have control same as open ice hits, and if you instead knock someone out you maybe... f***ed that up a little.
C.) The NHL and its fans concluded a long time ago that while things like shooting the puck change the position of your head and body, it's not fair to call that "putting yourself in a defenseless position" because it's kind of a really important part of the game. Cooke on Savard made that point crystal clear, not all plays are the responsibility of the puck carrier to avoid illegal contact. In this scenario Eyssimont could easily finish Jensen and remove him from the play without casting him into the wall.
D.) I posted the rule earlier so I'll say this again, because it's important: distance is not a factor. If I get my arms up into your chest and propel you 10 solid feet before you hit the wall but you still hit wall first, I still boarded you. Is that
normal? No. Did I, by my actions, cause you to go dangerously into the boards? Yes.
You're in a rush to defend to the point where I don't think you realize what's being said, and you're adding all this rhetoric like "giving up 30 lbs" when it just doesn't matter. There's finishing a check and then there's knocking a guy out with the base of the boards, nobody's calling for a suspension or saying it's premeditated, it's just a bad hit that
should be covered by that rule as written but isn't.
This is also a gap in their officiating as it relates to safety that I've been bothered by for at least like 10 years at this point, it's got very little to do with this specific hit. Hell, you're a Bolts fan, I've been on this one at least since Lecavalier tossed Jack Hillen and f***ed his shoulder/possibly career up. To me boarding should encompass more scenarios where players are not hit into the boards as a fluid motion but hit, thrown, and collide with the boards as a secondary impact. It's massively dangerous and the back-to-back impacts in different directions with no natural outlet for the momentum (like most on-wall checks) seem to increase the risk of injury/brain trauma.