I have no problem geocaching in a cemetery. Others have stated that it is a place of respect and a memorial to those that have gone before. Yes, that is true. However, cemeteries can also be places to learn of our past and meet those that have helped to shape our country. Geocachers, on the whole are respectful of the locations found in cemeteries.
I am aware that there are several large, older cemeteries here in Ohio that stage events throughout the year. For example, Green Lawn Cemetery, in Columbus just held events honoring Civil War members, WWII members, and have a Birder's Breakfast scheduled for July. I know that other cemeteries that offer tours of famous local graves or flower and tree walks.
it is, in the end, up to the individual cacher but, if the cache is placed in an out of the way location and the hunters are mindful of where they are, I have no problem with cemetery caches.