First of all, I believe that killing unarmed civilians is evil. But I know that this is not a problem for many leaders, including Putin, so I'm taking morality out of the equation in my question.
I completely fail to understand why the Russian military would do things like indiscriminate killing of civilians in places like Bucha, and why their commanders and top politicians would allow that.
To clarify what answer I am looking for: what Russia is doing in Mariupol is evil, but I can understand what their strategy is. They want to take Mariupol at any cost, and since they didn't manage to do it with infantry, they use indiscriminate shelling to create hellish conditions for the defenders.
But I cannot see any reasons why the Russian military would want to indiscriminately kill civilians on territories that had already been under Russian control. If they, for example, regarded Ukrainians as an inferior race that needs to be exterminated, that would be an evil reason to perform such acts, but there would be some consistency in it. But that doesn't seem to be the case.
What seems to be happening here are acts that go against the goals of Russia. It would make it more difficult to establish a pro-Russian government. It would create even more bad press for Russia.
There might be some consistency in it if Russia officially declared that it doesn't care about human rights. But Russia does want to be seen as a country that cares about human rights. Otherwise Putin wouldn't need to state that the reason for the "special military operation" is preventing genocide, and could simply admit that he wants to take the territory that he believes should belong to Russia and that he doesn't care how many civilian lives it will take.
And even if they intend to blame the Ukrainians for the massacres, it doesn't make much sense. They blamed the Ukrainians for a genocide in Donbass, even though there had been no proof that any genocide happened, and that propaganda seemed to work well within Russia. Which means that it's simpler to just blame somebody for committing atrocities, and there is no need to commit actual atrocities to do that.
Can somebody explain it?