There's nothing different between bringing a child into a crowd of people with signs and bringing a child to a crowd at an amusement park.
Uh, yes there is.
1. Carnivals are not called Slutivals
2. Carnivals are not anti-rape protests
3. Crowds in carnivals pay money to ride rides, not hold up signs and shout "DOWN WITH RAPE!"
4. Carnivals are specifically made to be kid friendly. Anti-rape protests are a bit more maturely-oriented.