Psalm 51:16-17 ("God does not delight in sacrifice") is situational to David after murdering Uriah — he can't just offer a bull and fix things. The only thing he can offer is a broken spirit. It's not a blanket rejection of the sacrificial system.

David has committed murder and adultery. Under the Law, there was no sacrifice for intentional murder — the penalty was death with no ransom allowed (Numbers 35:31). David can't bring a sacrifice to fix this. All he can offer is brokenness and repentance, throwing himself on God's mercy. Brian Zahnd misuses this as a blanket anti-sacrifice statement in his book. Psalm 51:19 shows that after restoration, proper sacrifices resume.