I went to church today and after church I said let me take my daughter to the park.. I'm in the park…

I went to church today and after church I said let me take my daughter to the park.. I'm in the park and there's a little 5 year old boy he stood right around my stroller where my baby was and when I was looking down at my phone he threw a stick at my stronger. I thought to myself "okay calm down this was just a coincidence he's just a little boy "then my older daughter was playing with some kids in the park and a kid called her a bad word or something so she came and told me mommy let's leave the park I said okay let's go and then she said it's okay mommy she went up to the little boy and told him that she's not whatever he said she was so they started playing I realized it's that same little boy I was looking at him and out of nowhere he started throwing sticks at my daughter threw one stick, threw another stick , and a third stick I got up I started screaming I asked him where is your mother and then I told him you cannot throw sticks at people do you understand? and he ran the other way and said "yes" my question is if you know your child and know he is rude why would you let him go to the park by himself ? I know we as parents know our kids really well! One he was too little to be on his own out and two he is not a quiet kid that wont get the attention of an adult !!!