The slave thing wasn't his idea. He was very displeased by it.

He wasn't freeing the girls in order to make himself a hero. It's just that when one beastfallen irks in humans, all the beastfallen will be the victims of that ill will. That's how it goes. When you are talking about a minority, every single individual represents them all in the majority's mind, especially in the negative aspects. I'm sure you have noticed that in Germany these days as well. Beastfallen are barely tolerated, and are considered below humans, so what do you think human dudes will think when they see a beastfallen walk the streets with beautiful human slave girls in tow? They will think all of those beastfallen bastards will need to be deported and a wall needs to be built to keep them out.