dd is 3.10, she keeps making rude loud comments.
at the park "mommy that boy is being naughty walking up the slide isnt he cos he might fall and hurt himself and making it dirty isnt he" loud and repeated when ignored, ive told her we shouldnt comment on others, she wont stop.
"mommy those big boys shouldnt be on the baby swings they are breaking them arent they" said to big scary teenagers 
"mommy that man is big/fat/hairy/tall/short/ isnt he"
"mommy is that a man or a woman"
problem is if i tell her not to do something she always says why so i give her a reason like walking up the slide makes it dirty for everyone else, then she feels its her calling to become the safety police and tell everyone in the park even if they are 15.
she also comments on her nursery friends, "why is X in a buggy/got a dummy like a baby" which comes across mean.
she also bigs herself up, like she announces she is the prettiest/cleverest/fastest, we tell her she is pretty and clever etc but dont compare her with others.
how do i control her mouth, do i ignore or keep telling her its rude or are all 3 year olds too talkative 