For every example you can find me of a website that doesn't support safari I could find 10 that make exceptions to do so. The point isn't that nobody does it, it's just that most companies who want to make money from the general population (aka most of them) have to.

Roll20 is also such a niche thing already it's not really a fair example. People who want to use roll20 will use another browser because they want to play dnd with their friends. Most stores don't have that social aspect.