This is the BIG QUESTION that you can expect to face endlessly. That this doesn't refute the law of identity, only that we haven't found the proper identity, is never entertained.
If the law of identity works all the time, than, pardon my french--it works all the time. If it doesn't work all the time, than it is not ubiquitous, yes or no? Oh, but wait, you say, SOMEDAY, we will discover just the correct way to turn our heads so that we see that it works for the 2-slit.
Now that's a devastating argument, isn't it? The fact is that one buckyball goes through two visibly separated slits at the same time. This nakedly violates Identity using very simple structures that you can easily draw venn diagrams around. So unless you want to claim that buckyballs can't be elements of sets when you figure out how to "see" this as NOT a violation of the law of identity, you will have also thrown out the rest of classical physics.
Why, because you say so?
How? I don't see how it violates identity even fully clothed.