Non-theonomists do not disregard the OT or GOd's law, they just believe that the switch in focus from the CIVIL GOVERNMENT that was also the church in Israel to the CHURCH in the NT calls for a view of general equity that is more in keeping with Paul's injunction to excommunicate than with the encouragement of execution.
A favorite bait of the theonomists is to say that one must choose either their form of theonomy or else they do not respect the law.
Again, here is a Biblical response to theonomy form Third Mill:
Both theonomists and other reformed scholars believe that the moral law continues into the present age and the ceremonial law has been abrogated by the coming of Christ, since He has fulfilled those aspects of the law in His priestly ministry. The point of discussion is over how the judicial law should be applied to the present age. It is important to realize that the Mosaic law "was accommodated to the people of God in their particular redemptive-historical setting" (Pratt 1990, 345). The Jews lived in the land of Israel and many of the penal sanctions (as well as the moral and ceremonial laws) were contextualized to that situation. For instance, "Prohibitions against stealing in the Old Testament included respect for a fellow Israelite's permanent land inheritance (1 Kings 21:1-19)" (Pratt 1990, 345). However, the Christian has no inheritance in the land of Israel. Our inheritance is the New Heavens and New Earth (Hebrews 4:8-11). The coming of Christ and the consequent disenfranchisement of the Kingdom of God so affected history that the proper application of the Mosaic law within the church must account for these situational changes.
John Frame has noted that the New Testament church "fulfills the Old Testament theocracy" (Barker 1990, 95). In applying the Old Testament laws to the church, Paul did not apply them exactly as they were applied in the Old Testament. For instance, In 1 Corinthians 5:1-13, Paul addresses a situation where a man is living with his father's wife. According to Old Testament law, the man and the woman should receive capital punishment (Leviticus 20:10). However, this was not recommended by Paul. Rather, the proper punishment of this crime for Paul is excommunication (vv. 2, 13). Furthermore, Paul's statement in verse 13 is a quotation of a formula found in Mosaic penal sanctions (Deut. 17:7, 12; 12:19; 19:21, 21:21; 22:21, 24: 24:7).
Dennis Johnson has noted that "in the Deuteronomy contexts this formula, whenever it appears, refers to the execution of those deeds 'worthy of death': idolatry, contempt for judges, false witness, persistent rebellion towards parents, adultery, and kidnapping" (Barker 1990, 181). These crimes were to be punished by purging the offender from the covenant community through his execution. Johnson continues, "Paul applies the same terminology to the new covenant community's judging/purging act of excommunication-- a judgment that is both more severe (since it is 'handing this man over to Satan,' an anticipation of the final judgment), and more gracious (since it envisions a saving outcome to the temporal exercise of church discipline, which may bring about repentance that will lead to rescue from eternal judgment)" (Barker 1990, 181-182). Therefore, it may be safely said that the proper application of those capital offenses of the Mosaic law are properly applied in the church today as excommunication. 3. Conclusion In 1 Timothy 1:8 Paul claims that "we know that the Law is good, if one uses it lawfully." Theonomists take this to mean that the law should be applied largely as it was in the Old Testament, without using it as a means of salvation and taking into account the explicit statements in the New Testament where certain laws have been abrogated. However, it appears that Paul's statements concerning the end of the law are somewhat more inclusive than this. The law, in its ministry of condemnation (2 Cor. 3:9), has been abolished and has replaced with the "ministry of righteousness" by the Spirit (2 Cor. 3:9-11). The law has been written on our hearts by the Holy Spirit. As we walk in the Spirit, we fulfill the law. This does not mean that the Mosaic law no longer applies to the Christian as a rule of life. Rather, it means that the law can no longer condemn us (Rom. 8:1) because Christ has satisfied the demands of the law in His life and paid for our sins on the cross, and He has sent us the Holy Spirit, by whom we are empowered to fulfill the law (Rom 8:2-4).
Furthermore, Theonomy fails to take into account the situational changes brought about by the coming of Christ in the application of the Mosaic law to the church. The Mosaic law was accommodated to the Israelites living in the theocracy of Israel. The church is the fulfillment of the Old Testament theocracy. Yet as a result of the coming of Christ, the Kingdom of God has been disenfranchised to include both Jews and Gentiles (Eph. 2:14-16). This situational change in the Kingdom of God necessitates a change in the way the law is applied to lives of believers.