I often will ask if I can get my slices from the point, it is just what I would prefer. If I am told no, or that folks don't get it, then I will order what I see that is on the menu.
As to right or wrong, I can't make that call for you, you went about it in a manner I would not have done, and your response leaves a bit of a sour taste in my mouth, as a former restaurant worker. But, I think you have a right to spend your money as you will, and if you need that answer to move forward with the order, than so be it.
me: I don't drink anymore
Yelonutz: me either, but, then again, I don't drink any less