You can send an e-mail to email@example.com and ask to have it removed.
As far as the site goes, it is a nonprofit site and the listings are free. The site is supported by ads. Yes, a sponsorship will remove the ads, but it also increases the photo limit from 5 to 20. Many people sponsor a memorial of a loved one and add personal photos to it.
The site itself acts as a virtual cemetery. The purpose is to document all graves because all stones eventually deteriorate. A modern stone may not be legible in 150 years. It allows people researching their relatives to locate their burial sites. It also allows people who live in other states to virtually visit their loved one's memorial when they are unable to visit in person.
Product or Service Mentioned: Find A Grave Website.