Birthday talk

Went to a birthday party this week-end. The party was a double party for a 22 year girl and a 3 year old boy. The party was held at the girl's house which she shares with her friend, the child's mother and her boyfriend, who just happens to be the birthday girl's stepbrother. That sounds confusing. Anyway, parents and friends were all invited. They had Moon Walk for the kids and cooked hamburgers and hot dogs. All the family and friends seemed to have a good time. My question is though, when it is appropriate to tell a 3 year old that "you make me sick", or "you're the scum of the earth". I know this was said in play, but since when do adults tell children things like that? Maybe I am wrong, but I dont think that was right, even it play. But no one else seemed to be the least bit phased by this. Well, if no-one else cares, why should I? Because,I am old fashioned(or out of touch with reality). I think that we should not talk to young children that way. But that's just me...