Because the boy on the right in this image has his face painted exactly the same way you jackass.
You can keep pretending that you don't see it, that doesn't mean it isn't there.
If you don't see how that can be perceived as racist, then you are either stunningly stupid or you are a racist yourself.
I'll let you decide which one of those you are.
I have no issue with 'paint-your-face-night.'
I do however have an issue with paint-your-face-like-a-Minstrel-Show-performer-night.
Here is a posting from a Kentucky Prep School message board, where one person commented on the make up that the kid on the right in the image was wearing.
http://archive.fo/fZRj1
Minstrelsy.
So it's not just me who thinks that makeup looks like something from a Minstrel Show you jackass.