It's pretty irrelevant what his backstory was in an early EA. If it didn't make it into the release game then it didn't happen.
I never came across him saying anything other than he was a magistrate and was set upon by the Gur who disputed a ruling he'd made (3rd playthrough). He just says Cazador found him bleeding out on the street. Now I am quite prepared to believe he took bribes or whatever - fits his personality. But the stuff about him double crossing Cazador way back when, I haven't heard him speak about or seen anything to verify it so if it was there in early EA it isn't now, the devs totally removed it.
Regardless, if you have been forced to torture others, been the victim of torture, even self torture, alongside much other abuse both physical and emotional then whatever he may or may not have done before being made a spawn isn't really relevant, if it was bad then he's paid for it many times over.
He had no choice re the children that appear later on, Cazador told him to and was capable of forcing him to, he almost certainly dissasociated himself from this sort of thing as a self defence mechanism.
He says it himself and nothing in the game contradicts it (even the Gur leader - and she should be the authority on this - says no one blames him).
But my take on why he doesn't empathise with slaves? Deep down he still is one. He's still scared of Cazador. Franky hes scared of a lot of things. And he covers it by being hard faced. He doesn't want to risk his life (if he cares for you he doesn't want you to either) for some random stranger. Can't say I can blame him for that, he's finally got some autonomy over his life for the first time in 200 years, why would he think risking it for a random stranger is in any way sensible.
As the player sitting in my comfy chair with absolutely no possibility of repurcussions beyong having to reroll a save - even I sometimes wonder why we do such things pretty muuch all the time in games rofl
The voice lines are cut, but there's an argument to be made that his backstory is still 100% in the game, unaltered. You'll know why it's still in the game as soon as you get a conversation going between the Gur and Astarion -- he very much still sold their children into slavery. Consequently, everything else likely remains true. What changed is that he's no longer *honest* with the player about why he died. Why he was turned.
Understanding his EA backstory (if you are a non-believer in my interpretation, that is fine), is also required to understand his attitude about slavery. Because those lines were likely written for EA Astarion, as we know him. As both of these aspects *are* theories about the game and his behaviour, I do call him "EA Astarion". The counter possibility is that the moment he turned a blind eye to slavery was retconned to post vampirism. I for one just doubt the Gur killed him over nothing. The Gur who actually knew who he was.
You can bet there is a fair bit of denial going on around "was I guilty enough to die?", and I do believe he uses that vehemence to say "no, none of this should have ever happened to me, because none of my actions were that bad". Finally, how he overcomes that inner conflict in both of his endings is drastically different, and will shape his personality for the better or worse.
