He said he didn't find pleasure in their burnt offerings or sacrifices For it wasn't benefiting them. They had to understand the awfulness of sin and death which when he said this there hearts weren't right. I don't like the idea of animal slaughter myself. I know man has done it for years as a means to survive. Now we have butcher houses but No I don't believe God found pleasure in burning flesh but peoples obedience that made the offering a sweet smelling savor. Since God told them he had no pleasure in this later on and it also says the man who is cruel to his animal will not go unpunished. I have to believe its spiritual and for the benefit of man who God created above the animals and a foreshadow of the lamb who would be slain for the sin of humanity.Like I said I can't even kill a bug so The thought of killing a animal for me is gosh awful as it was for some of them. But it was to show them how awful sin is to a Holy God. I may not seem fair but he made the animals and us so He must know best. Again I believe from reading the bible as a whole it was used to show man something not that he wanted to kill animals but he wanted to reach man and reveal their need of a savior.