You nailed it.
For the bulk of his career Brown had a reputation of hitting hard but clean. The only thing that's shifted is the Kings winning most of their playoff series the last two years. Well that, and other teams/fanbases melting down about it. Rozsival turned out to have a thigh bruise and they can't let it go, for the love of god. Was that what he was supposed to be suspended for? Or what, the slow mo gif of him hitting Jaden Schwartz in shoulder with his elbow?
The collision with Hertl is a good example of this. The textbook definition of kneeing is to extend the leg while going for a hit, and Brown doesn't even have weight on that leg (Hertl does). But Hertl goes down and suddenly Brown's the new Marchment, lol. Watch some actual Marchment clips and get back to us. If there had been any hallmarks of kneeing Brown would have been nailed to the wall for it, and their GM who loves gamesmanship would have howled to the moon over more than a lack of "manners." There is no magic no-suspension halo.
You know once someone posts "we know it has to be intentionally dirty, because it's Brown" that they have lost all ability to evaluate the clips front of their eyes. And they aren't going to post clips of Brown's other 2,000+ hits that are fine, because that's not the evidence they seek. HFBoards confirmation bias at its finest.
Want an actual dirty player? Torres has a rap sheet as long as my arm, and knocked out other players with a concussion three playoffs in a row. In each incident, he had plenty of time to make a better hit through the body and didn't. As much as Sharks fans would love to make him Brown's moral equal to feel better about Torres on their team, it is not even close.