As long as players are helping their teams win games, the fans as a whole seem to care more about winning than who their teams is winning with. Pair that with the amount on money coming from betting on sports online and there is a real disconnect between moral ground and a winning season.
Unfortunately, it will be a long while before we reach either of those points. Fans look to the league organizations, whether that be the NFL, NBA, MLB, NCAA, or others, when it comes to disciplining players. Until the leagues themselves step up their discipline standards, fans will continue to be okay in their eyes when they return back the playing field.
In our society people innocent until proven guilty and once found guilty must reap the consequences of their actions. Once those consequences have been served though, we like to believe justice has been done and the person should start with a clean slate again. Fans tend to stick to these ideals when their favorite players face criminal transgressions because not only do they look upon these players as idols but these players are the ones that are going to bring the fans city or alma mater to the promise land of championships.
Furthermore, fans justify the return of players with criminal transgressions with the logic of the other team has players like that so we should too.
Until leagues themselves start stepping up the severity of discipline, fans themselves will not change their standards on players with criminal transgressions. Once leagues do just that, you can expect fans to follow suit.