I've had this debate before with Christians, and as someone who used to be a Christian, I understand how the counterargument goes. Many Christians argue that the violence attributed to god in the Bible was a just response to a situation (like a punishment for sin), or some action which was justified by good coming out of it.
One of the problems with this is that most Christians are unaware of just
how violent the Bible is. A lot of Biblical passages are not mentioned in church at all, and I know that I was unaware of much of the brutality. Below is a partial list:
Jehova: "A Murderer and a Liar from the Beginning"
Many of these supposed actions cannot be said to be responses to a proportionate misdeed, as evidenced by the descriptions of innocents being killed and the level of carnage depicted.
Some Christians argue that even the most heinous acts of violence depicted within the Bible were justified by the even larger good to come as a result. But this flies in the face of the notion of an omnipotent god, as a truly all-powerful being would not be dependent upon violence to accomplish what they want. Ask yourself: If there was a famed surgeon who claimed to be "all-powerful", but he had to make painful incisions to heal his patient instead of just healing them through his will, would such a doctor be all-powerful?
You do not provide any, or even one, example in this claim of yours that may be addressed. That makes it hard to answer your question.
Thus a general answer will have to do.
Are any of the people who lived from 6000 years ago to even 300 years ago still alive today? Or, is everybody from even a hundred twenty years ago dead! If they all are dead, you cannot be objecting to them being dead, you would have to be objecting to their manner of death.
If this universe is an atheist (ha ha), then nothing matters for all shall disappear and be forgotten. What matters - matters only to the individual while that one lives, and thereafter, not at all.
If God exists, then why the suffering? Obvious, really! Our reality is a cause and effect universe, we rebelled against God and he lets us suffer the consequences. If he didn't, how could we know we made the wrong choice!
If then, in the past, God destroyed the wicked, and destroyed small nations to make his nation have a place to live, why did he do that, and what will be the ramifications of it?
Those he destroyed in the flood felt the rain, ran up mountains if they could to get away from the flood. Yet, they died. When some of these come back in Paradise by resurrection, do you think that they remember their terror? Of course the will. That means that they know God will kill them if they do not obey him.
Those who killed small children in Baal worship in among the nations that Israel were commanded to clean out, will if any are resurrected know that such abhorrent behavior, wickedness - will mean that they shall die the eternal death if they do so again.
The point being, God's actions in the past in no way prevents him from bringing anyone back he thinks merits this. Thus, his past actions are recorded for us to learn so as to refrain from doing evil, Or, Else.