I don't understand how children can be so cruel when they're just children. It's the responsibility of their parents to teach them right from wrong.
You solved your own questioning hehehe, they are just a parent's reflection. Kids aren't born with prejudices, parents just put them in their heads.
I have a story nothing related to trash. My former neighbor has two kids, one daughter that is the same age as my oldest ( she was 5 at the time of the occurrence ) and a boy aged 7 also in that time. Both kids were bullying other kids who weren't dressing like the sex that they were born. The mother was complaining about why she was called since kids do that stuff and it was normal... When a parent reacts this way, ignoring a problem it is because the parent agrees with that.
Let me share a fictional story related to it.
Son: "You do it because your parents taught you this," the son said to his father.
Father: "So, I taught you to disrespect my parents?"
Son: "But I was just appreciating your teachings."
Father: "No, you were disrespecting my parents' teachings."