Hader is going to face some major backlash. Constant booing and protests, and this will go on for at least the rest of the year, and probably follow him all of his career to a lesser degree.
It will also diminish his value considerably. A lot of teams (owned by corporations such as Rogers), won't be able to take him - and his market will be a third of the teams in the league. Attanasio should be able to weather the storm, but the Brewers organization will be inundated with letters and calls from people threatening to not go to Brewers games while he is there.
Additionally, you may see some pressure for other corporations to stop sponsoring the Brewers, until they get rid of Hader. He's offended three loud, vocal identity groups, so there will be no shortage of Hader haters.
Will be interesting to see what MLB and the Brewers do, given that he was underage at the time.
Still, this isn't going to be about what's fair. This is going to be about virtue signalling. It wasn't fair to ban Donald Sterling for life, based on the contents of a private phone call, but that's what they did.