Obviously, the gag in this film is lost on modern audiences. The obsessive and frustrating washing of the black boy is supposed to imply that no matter how hard she washes him, he is still black. People (white men) in 1896 thought this was hilarious.
As much as I would like to believe this kind of blatant ugly behavior was isolated, it wasn't. Racism is still prevalent today, but far less so than at the dawn of the 20th century. This film is an embarrassing reflection of its time.
Contrary to what a previous post claimed, you aren't racist just because you recognized the original intent of the film.
I think it is important to know about this film, but it is not important to see it.