Your example is flawed because thats not what is happening here.
Because in your example you would not sell anything to those people in the first place. These aholes did sell them something and now they are trying to use a deliverately vague clause to retroactively demand something of a business that has nothing to do with their product.
Point taken. I agree after the fact on something as complicated as software integration. But you should not have to sell something to someone if you don’t wish to.