Why are most kids brutally honest?

Some kid roasted me saying I look like the fat version of Princess Bells. She is very good at roasting and she's only 10. As age 10 I wouldn't even have the guts to roast someone. I was a huge crybaby and kids called me a crybaby and my parents would get tough on me and tell me to go back and talk to those kids and stand up for myself. Anyways I know my younger cousin was joking but it really offended me. Kids are so unapologetic.
She said, "More like The Beast and the Frog. I would have read a book before meeting you." The other two kids were like "Ooohhhhh!!!!" I just smiled and walked off. She said, "Hey I'm not done. Let me see some more pictures."
She said its a Roasting Challenge but I never wanted part of it