Sadly in recent times there is a lack of respect for those who come before us or for those who have served us. It is usually in teenaged kids or from those who are more affulent and believe wealth bestows privledges on them that everyone else doesn't deserve (There are plenty of great people who are wealthy, don't get me wrong.). Be glad you said something, too many times we just let it slide.
On a side note......
We have a veterans memorial in the small town where I live. It is within the fences of the city ballfield. Well, kids sit on it and stick their gum on it, throw balls against it and so forth. It kind of looks like a brick grill for barbecuing, but there is no open space. The names are on the front affixed to the bricks. It has a flat top where the kids sit and climb on it. My brother and I continually tell kids to get off of it and show some respect. My brother finally got tired of it. I don't know if you've ever seen Nevercease, which is used to keep bolts from sticking. Once it's on your clothes, it doesn't come off. Well, it just happens to be the same color as the mortar used for brick work. One night he snuck into the field and painted the top of the mortar joints with the goo. It took about a week, but the kids don't sit on it anymore.