Your "double standards" thing is a very simplified way of looking at the problem. Let's look at all these so called "---- only" entities. Black only, deaf only, Latino only, etc. etc. What's the common denominator in all of them. EACH ARE MINORITIES.
In the United States, white people are the majority, both in demographics and in political/social/economic influence. These entities, whether it is Ebony magazine or The NAD, exist as forms of empowerment for each minority group to counter the ingrained mentality that they are inferior, second class, objects, property, etc. (which, let's face it, is how they have been perceived in this country for a majority of its existence). White people do not need to form their "own" clubs and groups because they already control the majority. When a "white only" entity is formed, it is not a tool of empowerment, but a tool of oppression and preserving status quo power.
This "white only" basketball league is nothing more than a reaction to the loss of white control over the image of the NBA. It is racist, pure and simple. You can disagree with me, but until you go study institutional racism extensively, don't give me any armchair analyses. The problem is a lot more complex than your "oh, if they can do it, why can't we?" logic.
I am not saying that certain organizations (take the Black Panthers for example) aren't racist (because they most certainly can be), but their existence was born out of oppression and a need for empowerment.
Having a "white only" club is not the same as having a Deaf only club, or a black only club. Not in this country.