Ok.
Of course I don't support genocide. To even say I do prevents discussion also. But I'm trying to take it you didn't mean so because of misunderstanding and wordings.
We seem to agree genocide is the attempt to eliminate an
ethnic or racial group from a wide area (more than just one town),
because of their ethnicity or race. (at least this is what it means to me)
I don't support that.
And neither does the Bible.
Instead, analogous to the U.S. in WWII, the motive for wiping out a town was
not in order to kill people because of their ethnic or racial identity. Not the motive. While the U.S. motive was to try to end the war more quickly, the motive in the Bible in Deuteronomy-Joshua was different from the U.S. in WWII, but was
definitely not about race or ethnicity.
Therefore it was not genocide of course, but something else. Just like the U.S. killing 100,000 in Tokyo in one night was not genocide.
In the scripture, the motive to wipe out certain area cities (not every city, but certain ones) was given in such places as Deuteronomy 12:29-31 --
about the particular evil being done in those cities.
Because of that extreme evil, those cities were forfeit, God decided. And additionally their evil culture was to be destroyed to the extent it would not come right back a year or 10 later.
Also, God appears to have wanted Israel to understand that child-sacrificing idol worship leads to total destruction (everyone sent on to Judgement Day immediately, where the innocent will be separated away from the guilty after the fact).
The experience of destroying the cities, for Israel, was to be a lesson -- this evil leads to total destruction. (Also, we see in the text that Israel often decided not to entirely destroy various cities....)
But...
Israel would later in time come to do that same evil. In spite of the repeated warnings.
And Israel itself also would be devastated in result, with massive death and destruction -- it's all there in the Old Testament.
Israel got a similar extreme punishment when it's people began sacrificing children on altars.
There was again, just like before, no motive for that destruction of Israel that was about race or ethnic identity.
It was entirely about ending the evil, just like before. Same reason.
If you read through all the Old Testament you'd encounter the short Malachi chapter 4. It could help clear up a lot here. (just 6 verses also)
Malachi 4 NIV
See, unless humanity changes and loves its children, verse 6, loves children instead of killing them, sacrificing them...God would (however often needed) come and totally destroy the land (city, nation).
See it there?
The message given many times in the OT (and sometimes in the New) -- He is slow to anger, but will not tolerate the extreme evils forever.
He will destroy them.
So, if
you are actually against slavery and genocide and child sacrifice and other evils...then
you are aligned with God in that way.
But God appears to intend not merely to promulgate laws that people won't follow in their true spirit.
-- if they didn't want the change they would just go around the law and just end up doing the same evils in new ways, usually even worse! (and that happens plenty also in the scripture, over the chapters)
Not enough. He wants actual results -- real change. Not just laws.
He wants us to actually stop doing the evil. Not merely make a law against it.
He intends true change in human hearts, so that we don't even want to continue doing evil. The law is only to aid as a teaching tool, but can't run far ahead of where human hearts are ready to go.
So, first God had to gradually change our hearts. And that's a deeper story you can see in the Old Testament, very plainly and clearly, if you read through.