But God is all-knowing, he basically set a trap on them knowing the outcome. He knew he was going to punish humanity even before he created the universe.

Genesis still has some remnants of when yahweh wasn’t triple-omni. E.g. when he comes into the garden of eden after they ate the fruit, he asks what have they done as if he didn’t know yet. So he likely isn’t omniscient in the lore yet. If we wanted to be charitable, he’s just a sociopath here, and not a sadist that created a species already knowing he’s gonna punish them forever