The point is that I have some faith in my own ability to discern right from wrong, and I wouldn’t abandon it just because someone else came along and ordered me to,
This is insightful, is it not?
You have every reason to trust a 1.4 kg lump of flesh with, perhaps, 20-60 years of empirical sensations to go by, but NO reason to trust an omniscient, omnipotent, omnibenevolent God, as if you have the wherewithal to distinguish between just “someone” and God. In any case, perhaps the fact that you admit to being completely unable to distinguish God from “someone” or anyone else should give you additional reason not to trust your own judgement.
… regardless of how powerful or benevolent that person claimed to be. If God (with all his omni-s) really wanted me to do something, he would be able to convince me to, but I’m not going to make it trivially easy for him. A human life is worth giving even God at least a little push back (e.g. What if there are fifty righteous people in the city?)
That’s just it, you see. This “command” by God to Abraham didn’t just come out of the blue, it was based upon a whole lifetime of Abraham’s experiences with God. Abraham did a whole lot of “pushing back” - (his call, Sarai, journey with Lot, sojourn in Egypt, the covenant with God, Hagar, the three visitors, Abimelech, birth of Ishmael and Isaac, etc.,) have you not read the entirety of Genesis? You seem to forget that Abraham, who gave God a little "push back about Sodom and Gomorrah, saw how they had been destroyed by “someone” with the power to rain fire from Heaven. You are claiming your little 1.4 kg brain, possibly with memory and attention deficits, should still be trusted above a lifetime worth of definitive proof that was provided to Abraham?
Certainly, it is not clear how the cumulative case offered by your life experiences and your ability to draw conclusions from those experiences should, a priori, trump the cumulative case offered by Abraham’s experiences and rational capacities.
If your claim amounts to, “Well MY experiences are not Abraham’s!” Fair enough. But don’t go faulting Abraham merely on that count.