I don't understand what the image is depicting exactly, there's one black person in the picture and she's sitting there while that guy is about to drip something on the head of the woman next to her?
Is it a picture of white people bullying a group for having a black friend?
This is from the Woolworth's sit-in, where people sat at the segregated lunch counter in protest.
Other people who did not like this verbally and physically abused them.
Also, the white guy covered in dessert is presumably an ally there to show solidarity and, judging by the size of him, also physically protect them if necessary.
Lunch counters were segregated in the US. A fairly common protest was black folk sitting at lunch counters and trying to order lunch. This often causes uproar and unrest, riots. I believe the woman who's about to have water poured on her head is black, it's just that the picture makes her look white, or she's fairly passing.
They’re having salt dumped on them too, for the grave offense of sitting at a Whites-only lunch counter.
If this mob of hick bullies wasn’t there to torment them, well, black people might eat lunch there. Obviously that would be the end of the world, and all would be lost.