the gur are always fairly polite when I deal with them they talk about Astarion being changed and though he lived a life of violence and sin he can yet be redeemed, if he remains a spawn but sacrificed the children he says he did them a kindness so the gur didnt have to deal with it and Ulma says she would prefer the choice however she agrees to no longer hunt Astarion and will be there in the final battle.

I do however fight Gandrel every time though so he never makes it to act 3 .
( I like Astarion either way AA/UA )