THere are a few things to consider here. I won't even bother trying to state all of them, but just a couple that come to mind.
1. The NBA is a monopoly that should violate several anti-trust laws. The reason it (and other sports leagues) are allowed to exist is because, legally speaking, they are equal partners with an official employee player's union. If owners tried to collude to make a league and were negotiating with players individually, I believe that would be fully illegal by anti trust laws. So the players (and their union) are not inconsequential as the OP believes; the existence of the union is actually necessary for the league to exist in the USA, and is in fact a critical partner of the league's existence. This is not some helpless victim getting bullied here.
2. Shouldn't we appreciate that a majority of employees has some ability to cast off a hateful despicable millionaire? Are we really at a point where we worship the possession of money so much that we celebrate someone like Sterling's untouchability? It's one thing to wonder about his legal rights (though of course the US constitution does not apply here, he is not facing any legal consequences; this is a business partnership, like a board of directors forcing out one member that is damaging the company), but it's another to celebrate and root for his "right" to simply use his power and money to continue making lives crappy for his employees, tenants, etc. With campaign finance laws, recent changes to legal systems, Sterling support, etc, it really seems like we are increasingly putting more and more value on being able to consolidate money in an individual's possession as a societal ideal increasingly farther and farther above public good, the moral considerations of the many, etc. Do we really want the sum total and defining ideal of America to be $$$$$$$$$$?
3. Related to the above point, it's really interesting how we really seem to be slipping more and more as a country toward complete corporation immunity and power, but then I think (and this may be a generalization), many of the people who support coporate worship are protecting Sterling. I don't think you can have it both ways. The Pro-corporate laws (ie antitrust exemptions, ability to put the bottom line before ethics, etc) really seem to be what is going to allow the NBA to evict Sterling without much legal opposition.