Now, if an owner instructs his ticket-takers at the home arena to disallow blacks to attend games, that is an "act". Telling one's mistress not to publicly bring blacks to games in a private conversation is not an "act".
One can argue that they overreacted to the racist ramblings of a stupid old man, but having decided to act I disagree that Silver used the wrong clause to nail Sterling with.
I am having trouble deciphering two things with this sentence in your post: (1) *Who* "decided to act" in your opinion and (2) *what* was the "act" to which you refer?
Perhaps posting the clause in question would help, Article 24 (l). The pertinent section is in bold. "The Commissioner shall, wherever there is a rule for which no penalty is specifically fixed for violation thereof, have the authority to fix such penalty as in the Commissioner’s judgment shall be in the best interests of the Association. Where a situation arises which is not covered in the Constitution and By-Laws, the Commissioner shall have the authority to make such decision,including the imposition of a penalty, as in his judgment shall be in the best interests of the Association. The penalty that may be assessed under the preceding two sentences may include, without limitation, a fine, suspension, and/or the forfeiture or assignment of draft choices. No monetary penalty fixed under this provision shall exceed $2,500,000."
As you can see the clause is written so vaguely that Silver has wide authority under it. Loss of revenue. Harming the relationship between the league and its players. Causing sponsors to leave. Damaging the reputation of the NBA. Sterling's comments caused all of those, in Sliver's opinion, and triggered his 'best interest of the association' excuse for hitting Sterling with the higher fine. He has those powers.
He could have nailed Sterling with a lifetime ban and a million dollar fine under Article 35A (c). But that may require intent, which is hard to prove. The powers under Article 24 (l) can be based on his opinion alone. He doesn't have to prove anything.