Technically this wasn't an actual wedding. It was merely an engagement party.

U.S. forces bombed and conducted airstrikes apparently targeting an engagement party in the northern city of Jarchi, Afghanistan Sept. 3, according to a Buzzfeed News report published Saturday.
... The bombing struck a congregation of family and friends who were celebrating the return of Ahmad Zai, a member of the Afghan National Police who had been away for four months while fighting against the Taliban, as well as his cousin's newly announced engagement.
It was at about 9 p.m. when the explosion occurred, as family members were "drinking tea in the garden, waiting for sweets to arrive," according to 20-year-old Mohammad-Agha, who was badly wounded in the event. "At 3 p.m. my son came home,” Shir-Agha Mohamed, Zai’s father, told Buzzfeed News. "By 9 p.m. he was dead."

Now to be fair, all the victims were guilty of being Muslim. More specifically, they were guilty of being in the proximity of our bombs when they exploded, and not being Americans.
Which means that this was just a minor mistake with no one to blame.

But it got me to thinking: how many weddings have we bombed?
This article from 2013 says at least eight weddings.

given the history of US war-making since December 2001 when the first party of Afghan wedding revelers was wiped out (only two women surviving), would have been: “A US drone…took out a likely target.”
After all, by the count of TomDispatch, this is at least the eighth wedding party reported wiped out, totally or in part, since the Afghan War began, and it extends the extermination of wedding celebrants from the air to a third country—six destroyed in Afghanistan, one in Iraq, and now the first in Yemen. And in all those years, reporters covering these “incidents” never seem to notice that similar events had occurred previously.

That sounds about right, except that when I kept looking it appears that eight may be a conservative estimate.

There have been numerous U.S. air attacks that have killed dozens since the Gulf War. These include two potential strikes in Syria just this month, the 2015 Kunduz Hospital strike in Afghanistan, and roughly a dozen errant wedding party strikes in Iraq, Afghanistan and Yemen over the years.

So maybe a dozen...or so.
Who really knows? Does any American really care, since they weren't Americans?
There is only one kind of acceptable racism in the United States today - discrimination based on the color of one's passport.