For what it’s worth, Johnson hasn’t been entirely blameless as much of the cast is apparently annoyed with Johnson for making the post in the first place and making the issue public.
While everything is still mostly rumored at this point, the word at the time was that The Rock took issue with how Vin Diesel was handling his role as a producer on The Fate of the Furious.
As a producer himself, Dwayne Johnson obviously has his own ways of doing things and whatever reason Diesel’s methods frustrated the actor to the point where he vented those frustrations via Instagram.