I knew the meme of people hating Wulbren, but he actually made a decent first impression on me, because he wanted to free the Tiefling prisoners. I was then surprised with how dismissive he was of Barcus, and I saw red in act 3, when he said, "Quiet, Barcus. The adults are talking." I found your diary, Wulbren. I know you used to be friends.
I really liked their story. It's very satisfying to take down Wulbren, and Barcus has such a great arc for someone who's just a side character.
I always thought, that Wulbren being mean to Barcus was to drive him away and out of danger. I do think he is annoyed that Barcus is so adamant against killing the Gondians, but I also think he still does like his friend.
And yes, he was honourable towards the tieflings, when he just could have ran away.
I don't get the hate for Wulbren either, when people like Gortash, Raphael,Orin etc are right there. But I guess people find all kind of excuses for characters that are 'hot'.