Welcome to the Cellar, Claud, nice to have you on board
I can't imagine how difficult it must be for people when the funerals of their loved ones are disrupted in this disgusting and callous way. To intrude on something so private, so individual, is utterly shameful. We only get to bury our dead once and how it's done can have a profound impact upon the grieving process.
I don't know how practical it wold be, and am very uncomfortable about anything which could potentially limit general rights to protest, but i think there's an argument to be had for wide exclusion zones around cemetaries and crematoriums. Nobody, regardless of the circumstances of their loved one's death should have to experience that.