Mike, you omitted this part of the Wikipedia article:
History
"The first known observance of Memorial Day was in Charleston, South Carolina in 1865; freedmen (freed enslaved Africans) celebrated at the Washington Race Course, today the location of Hampton Park, and each year thereafter. African Americans founded Decoration Day, now referred to as Memorial Day, at the graveyard of 257 Union soldiers and labeled the gravesite "Martyrs of the Race Course" on May 1, 1865. Black Charlestonians created this American tradition.
In the North
The friendship between General John Murray, a distinguished citizen of Waterloo, New York, and General John A. Logan, who helped bring attention to the event nationwide, was likely a factor in the holiday's growth. On May 5, 1868, in his capacity as commander-in-chief of the Grand Army of the Republic – the organization for Northern Civil War veterans – Logan issued a proclamation that "Decoration Day" should be observed nationwide.[6] It was observed for the first time on May 30 of the same year; the date was chosen because it was not the anniversary of a battle. Congress has a bill in the works to change it back to May 30 instead of the last Monday of the month.
There were events in 183 cemeteries in 27 states in 1868, and 336 in 1869. The northern states quickly adopted the holiday; Michigan made "Decoration Day" an official state holiday in 1871 and by 1890 every northern state followed suit. The ceremonies were sponsored by the Women's Relief Corps, which had 100,000 members. By 1870, the remains of nearly 300,000 Union dead had been buried in 73 national cemeteries, located mostly in the South, near the battlefields. The most famous are Gettysburg National Cemetery in Pennsylvania and Arlington National Cemetery, near Washington.
The Memorial Day speech became an occasion for Veterans, Politicians and Ministers to commemorate the War – and at first to rehash the atrocities of the enemy. They mixed religion and celebratory nationalism and provided a means for the people to make sense of their history in terms of sacrifice for a better nation, one closer to God. People of all religious beliefs joined together, and the point was often made that the German and Irish soldiers had become true Americans in the "baptism of blood" on the battlefield. By the end of the 1870s the rancor was gone and the speeches praised the brave soldiers both Blue and Gray. By the 1950s, the theme was American exceptionalism and duty to uphold freedom in the world.
Ironton, Ohio lays claim to the nation's oldest continuously running Memorial Day parade. Their first parade was held May 5, 1868 and this town has held it every year since."
The point is that there was a notion after the Civil War, in many parts of the country, that we should remember those who died in the war, which notion was then manifested in various state as holidays and was eventually adopted as a Federal holiday. No matter its origins, it is an occasion for us Americans to remember those who died defending our country.
Prost!
Brad