The meaningfulness of 'putting yourself in someone else's shoes ' thought experiment

Every time I present this thought experiment inevitably some freewillist will say something like "if i swapped places with you I would just be you, so the thought experiment is pointless", but here's the point:

It has to do with how committed you are to the idea that the past doesn't determine your actions.

Let's say that you were born with my genetics, at the same time and place, to the same parents and everything in the universe was the same down to the molecule. Those facts are all related to the past, but if you believe the past doesn't determine your actions, you're committed to the idea that you could do better than I did with those circumstances or at least you could act differently.

I've been in debates where the person will say they actually could do better than me. I think this idea comes from the ego because they are judging me from their own current perspective, not the perspective of someone who was born when/where I was, to the same parents with the same genetics. From their own perspective they are morally superior to me (these debates often occur over some horrible sin I've committed that they think they are too good to commit themselves) and thus their moral superiority would carry over into my circumstances.

The idea that the thought experiment is pointless because you'd just be me isn't a refutation of the thought experiment it's actually conceding that I'm right and the past does determine your actions. The fact that you'd just be me is the whole point.