It's not deemed to be racist, it is racist. You can't profess to be ignorant of the history and implications of blackface.
If your little white boy wanted to blacken up his face, I hope you, a socially aware adult, would explain why it's inappropriate and it might hurt the feelings of the black children in his classroom.
Children can do that stuff. My little boy once told a black child in our car that he thinks black people are disgusting, it caused an enormous offense and I was mortified. But it was a good opportunity for a conversation.
When Megyn Kelly, a noted
race baiting 'journalist' who is also an adult who can damn well take responsibility for her own actions, feigns ignorance over the legacy of blackface, you'll forgive me for not rushing to her defense.