Okay, let's say you like all the flavors equally. Then the choice will just be random. But if you like one flavor more than the others, you will choose that one. Or if you haven't had one flavor for a long time, you might choose that one.

Do you see? If there is a reason for your choice (e.g. it's your favorite or you haven't had it for a while), there is no freedom because you will just choose that one. But if you like all favours equally, it's just random so there's not really any will involved.

You can have freedom, or you can have will, but you can't have both at the same time. Something is either caused by another factor (therefore it's not free) or it's random (therefore there is no will). Something can't be free AND have a cause.