Rather than paint over graffiti, on a brick wall that you wouldn’t paint otherwise, power washing can completely remove it. You shouldn’t have to worry about your young child looking at a publicly visible wall and asking… “Mommy, what’s a &^%$?”.
Here’s a brick wall with graffiti spray painted on it. (foul language obscured).
Here’s the same brick wall after Joe saved the day and made this a clean, family safe environment again.