It is interesting to see this is an issue worldwide - See this blog post from America.

Here is an small excerpt:

"Most people don’t want dogs peeing and pooping on or near their loved ones’ graves, and chances are good that nature will call at least once during your stroll through the headstones. Should your pup happen to do their business on someone’s actual headstone or grave marker, you’ll look like an irredeemable asshole—especially if you forgot the poop bags at home.

Potential grave soiling isn’t the only reason to keep dogs out of cemeteries. Our canine companions aren’t just cuddly pals; they can also be talented escape artists, ditch diggers, thieves, chewers, and resource defenders. To a dog, grave offerings (especially stuffed animals) can look an awful lot like fun toys, and the people who came to mourn can look like new friends—or worse, potential threats. Are you ready to explain to a stranger why your dog ate the stuffed bunny they just laid on grandma’s grave?"

https://lifehacker.com/is-it-ever-ok-to-walk-your-dog-in-a-cemetery