It is serious for him, serious in the sense that it was/is his livelihood and to have all of that fucked up because of Russo (and his ilk -- which has directly led to where wrestling is now [ignoring COVID] and the much lower crowd/viewing numbers than any time previously). You put decades of work into helping nourish an industry by protecting it and not exposing the talent and to have it fucked with because someone thinks they can tell a story but has never been near a ring (or locker room) and doesn't seem to actually care about the talent... yeah... there's cause.
Let's put it this way, Cornette's affectionate name for him is "Shitstain", the level of contempt and hatred he has for Russo is nearly unlimited from what I can tell... and only a bit theatrical (would Cornette go and piss on his grave if he could get away with it? I suspect he would... but if he couldn't help himself and couldn't get away with it, he'd make sure to film it).
Never knew much about New Jack. He doesn't seem like a person I want to spend quality time with...