If I was Harrison, I'd file a lawsuit....Drag the NFL and Goodell into court, and make them prove why these hits are Fineable/Suspendable.....
Never work. Burden of proof would be on Harrison as plaintiff to prove they weren't illegal, and since the Goodnfl says they were, they were.
I don't think the legality of the hits would be the issue. I think it's the arbitrary and inconsistent application of the rules and penalties associated with them. Or, to put it another way, he's being discriminated against by the league.
FWIW, I wouldn't go down that road...if he wants to continue playing in the league, anyway.