I’ve never understood how one can just throw out half their holy book because their God (supposedly) decided to change the rules. This does not change the fact that he (supposedly) did these evil acts. If you just ignore the parts of the bible you don’t like, God’s a pretty great dude! An argument against Yahweh’s character does not change depending on which parts of the bible are still valid, unless your claim is that the old testament was never valid. In which case, why believe any of it?

Regardless, even the new testament depicts a despicable being. Would it not have been easy, as an all-powerful and all-loving god, to tell people not to own slaves? But no, instead in the new testament slaves are told on multiple occasions to obey their masters. One can preach about love all they want, but when their holy book endorses slavery, I cannot take them seriously.

Regarding your last point, that’s just false. I can criticize the Joker as being evil for killing hundreds, thousands of people. That doesn’t mean the Joker or Batman are real. That’s because I’m criticizing a being described in a story, not something I believe is real.

Edit: I, too, will extend my thinking here. If you believe in an all-powerful and all-knowing god, you need not even look any further through scripture for evidence that he is an evil being. He had the power to create any world with full knowledge of what would be to come, and the world he chose to make was this one. One rife with childhood cancer, slavery, starvation, torture, and natural disasters. This is not a world created by an all-loving being.