Because who needs causality, anyway?
A man walks into a barber shop and says, "I want a shave." The barber gives him a shave, but the man is also a barber. What happens when he walks in next?
What if your grandfather had never married your mother? Would you still exist? Or would someone else have been born to take his place?
What if everything that's going to happen has already happened, and it's all predetermined? Does that mean you have free will or not?
A man travels back in time, but his actions create a timeline where his parents never had children. Is that still him? Or is it someone else?