IMHO Yes it is a bad thing. If a person does not even bother to learn, understand or remember that Memorial Day is held in memory of our fallen soldiers then that means they are not sincere in the least.
Before it was Memorial Day, it was Decoration Day. A day to decorate the graves of the fallen in the Civil War. So it has always honored the dead. In states that sent soldiers to both sides, a sign of reconciliation was the practicing of decorating the graves of both Union and Confederate soldiers (which would be condemned today because of—racism). After the Spanish American War the decorating was done for the fallen of that war as well.
Veterans are honored on Veterans’ Day, which also has changed names. When I was growing up, it was Armistice Day, remembering the end of WWI. As time went by and WWII and Korea came along it was expanded to include all veterans, not just the WWI vets.
I guess the lesson here is that the passage of time means that unforgettable events, do in fact, become forgotten. As the people who lived them (and their children) pass away things fade into the mists of time.