You could also ask Why did Lestat love Armand after what he did to him? 

They’ve both done terrible things to each other but there’s a sense of peace now. They sort of consider themselves brothers. Deep down, I think Armand finds Lestat inspiring in his indomitable nature, and Lestat is more than a little intimidated by Armand’s intelligence and Mind Gift. They’ve both suffered a lot in their lives and afterlives and had to find reasons to go on.

^Here’s Owl!Armand and Cat!Lestat [X]

Lestat: “no means NO armand” *boops his nose*