I need to do some searching to confirm this, but it's my understanding that other cultures use white for mourning and other colors for wedding. Assuming Vera Wang designs for the world - and not just the Unites States - I fail to see how black wedding dresses are for the bride that does not care about etiquette.
Also, how on earth is the color of the dress tied to etiquette? IIRC, white wedding dresses became fashionable about 100 years ago.
I'm being too lazy to read the rest of the thread to see if this had been answered so I apologize if I repeat info. However, when I was researching wedding dresses a couple of years ago, I read somewhere that white wedding dresses became the norm after a queen (I think it was Queen Victoria) wore one. It came to represent that a bride had enough money that she could afford to wear a dress that would only be used once.
As a former women's historian, I can confirm that it was Queen Victoria's wedding gown that set the NEW standard for gowns. However, it did not happen overnight. Historically and for a long time after QV, the standard for a bridal gown was to wear THE most fashionable outfit you could afford. If fashion dictated that pale blue was THE color that year, brides wore pale blue. If colorful brocades were THE hot look that year, brides would have worn colorful brocades that year. ETc.
QV married in 1840, but it was only around the 1880s-1900s that a white and highly elaborate gown become common for a wedding outfit and even then, the use was largely limited to those in the middle and upper classes. Rural and working class women were much more likely to buy a new "best dress" to wear for the first time on their wedding day with the intent that they would then wear it on "best dress" occasions for as long as possible thereafter. I read in Lady's Godey's Book and other local women's magazines many articles about appropriate wedding wear and the editors most often recommended dark colors and patterns (including plaid) as they would "wear better" in the long-term.
So it wasn't really until the 1880s that we start to see a lot of white wedding gowns. And even then, there were cultural variations in this country. I have a lot of pictures in my vintage wedding photo collection of German-American and Czech-American brides in black or dark colored gowns (their bridal state is indicated by the veil and trail of flowers down the sides of their heads). In the 1920s, white was the most common color, but it was the flapper style. In the 1930s, white often (but not always) took a backseat to more practical colors -- it really depended upon your financial status. It was really only in the post-WWII era, that the so-called "traditional" big white dress worn only once (and put away) became the norm. So it's not really traditional at all!
To sum up: Wear what you want!