Jonathan, you can submit changes to Find A Grave and they are declined because their information 'is better than yours', or so they think. I send source citations when I submit changes and I normally get updates, but not always. With their auto updates, incorrect information can be introduced also. They are False Suggestions when the 2 systems differ and wikitree is correct. If Find A Grave is not going to update, you can't always make them the same. Gravestones also differ. Those pages will not be changed.
Anyone can always review false suggestions and correct them. I do that frequently. Many people mark all Find A Grave and Wiki Data suggestions as false stating 'I am not going to deal with it' or 'I don't understand it' or 'I didn't put that info in'. I find those reasons very unfortunate and incorrect for people to use, which is why i review False Suggestions.