I don't think it's really that bad, how they are keeping them.
If the snake is not a water dwelling snake, then it is not really a problem. It looks like the betta has it's own side, and the snake has one of it's own, I can see part of a dry land.
The only problem would be if the people were not careful about it, like making sure no accidents would happen.
Yea, that looks a bit too close, but maybe the snake doesn't actually try to eat the betta, they did say the betta attacked the snake, it probably thought it was food.
"Life is an adventure full of beautiful things, and a treasure worth more than gold."