Why isn't God more humane? After all, He punishes people and in the Old Testament had them killed. So, why is He so tough? Why isn't He more humane, gentle, and nice?
To be humane means to be characterized by compassion, sympathy, not wanting others to suffer, etc. But at the heart of the word "humane" is 'human.' So essentially the questioner is asking God to be more humanlike and act in a manner consistent with human standards. This is the wrong approach. To ask why God isn't more humane is to ask why God isn't more like people. People are sinners who contradict each other, have conflicting ideas, and are most certainly not the standard of righteousness. Furthermore, if there was a universal standard of "humaneness" to which God should obligate Himself, then how could such a standard be maintained as being true from a human perspective? Can humans develop a universal standard by which to determine what is truly "humane" and then ask God to fit into that mold? Of course not.
The fact is that God is holy and we are not (1 Peter 1:16). He does not sin, but we do (Romans 3:23). Because of His holiness and His righteousness, He must punish the sinner. The punishment is everlasting because God is infinite, and those who sin against him have offended the infinite God. But, God provided a way out of this judgment by having Jesus die on the cross and rise from the dead (1 Peter 2:24; 1 Corinthians 15: 1-4). This is called the gospel.
In the Old Testament God was harsh with nations around Israel in part to ensure that the nation of Israel would survive and provide the Messiah. God did not want it destroyed by the paganism surrounding it. So, when God acted with harshness to pagan nations, He was ultimately preserving the nation of Israel through whom the Messiah would come. Without the Messiah, no one would be saved. So He was ultimately protecting us. But is this a humane thing to do? Is it humane to give yourself over to a horrible death so that others might live? That's a debatable topic, but one thing is for sure, God is far more "humane" than we are in that He gave Himself for us (John 3:16).
So, even though some people might say that God is not as kind or as compassionate as they want Him to be, particularly in the Old Testament, they should realize that God is exceedingly "humane" in His display of compassion, patience, and kindness as He endures the insults against His Holiness by the people who sin against Him. Yet, at the same time, He patiently waits for them to receive Christ as Savior.