They weren't innocent? Okay let's see. Here is a list of just a section of the people killed in the Old Testament:
1. A man who refused to impregnate his brother's widow (Ge 38:7-10).
2. Two men who offered God incense that he had not authorized (Le 10:1-2).
3. A group of about 300 people who opposed Moses politically (Nu 16:1-35).
4. Another group of 14,700 who sympathized with the first group (Nu 16:49).
5. More people who complained about the food and other matters (Nu 21:4-6).
6. 24,000 more because of some who worshiped Baal (Nu 25:3,9).
7. The Amorites who besieged Gibeon (Jos 10:10-11).
8. Seventy men who looked into a box (1Sa 6:19).
9. Another man who, with good intention, touched the box (2Sa 6:6-7).
10. A man who refused to use his weapon against another man (1Ki 20:35-36).
11. Forty-two children who called Elisha "baldy" (2Ki 2:23-24).
12. 185,000 Assyrian soldiers (2Ki 19:35).
God also killed all of Pharaoh's horsemen in the Red Sea (Ex 14:26-28). He could instead have simply made their horses lame, which would have been far more effective than removing the wheels from the chariots so that the horses had to drag the chariots slowly along the ground (Ex 14:25). That would have also spared the horsemen.
In addition to killing people directly, God also ordered several people killed (despite his commandment not to kill). Here are some examples of people who died by God's order (and in some cases with God's help):
1. Three thousand of the Levites' brothers, friends, and neighbors, who had become unruly (Exodus 32:27-28).
2. All the men, women, and children in all seven of the tribes who were the Israelites' neighbors (Dt 2:34, 3:6, 7:1-2,16, 20:16-17). [Some Biblical verses imply that the Israelites numbered 2-3 million, which would make the total population of their neighbors more than 14 million. What God was here ordering, then, if we could go by those verses, was a kind of Holocaust.]
3. All the men, women, and children of the cities of Jericho, Ai, and dozens more cities and towns (Jos 6:21, 8:24-26, 10:26-42, 11:10-23, 21:44).
4. All the Amalekites, including children, and even animals (1Sa 15:3,18), [where Saul was severely punished for sparing some of them].
5. All the members of the house of Ahab and ministers of Baal within Israel, the latter accomplished through deception (2Ki 10:11-25), though approved by God (10:30).
6. All the citizens of Jerusalem, including children, who did not grieve and lament over sins committed in it (Eze 9:4-6).
It seems quite unethical for God to order the execution of so many people, whatever their offense might have been, especially in the case of the children, who were presumably innocent.
Closely related to the above is the extravagant use of capital punishment among God's chosen people. God ordered people put to death for such minor offenses as the following:
1. Consulting a witch (Le 20:6; Dt 18:11).
2. Blasphemy or merely having a different religion (Ex 22:20; Le 24:10-23; Dt 13:1-15, 17:2-5, 18:20; Jos 23:7,16; 1Ki 18:40).
3. Gathering sticks or kindling a fire on the Sabbath (Ex 31:14-15, 35:2-3; Nu 15:32-36).
4. Eating the wrong food (Ex 12:15,19; Le 3:16-17, 7:22,25-27, 17:10-16).
5. Being a disrespectful or disobedient child (Le 20:9; Dt 21:18-21).