RE: Alignment

D&D is a game, not a simulation of real life if magic and monsters existed, or a logical treatise on morality.

The point of alignment in the context of a game is to provide a shorthand way of describing your character, NPCs, and monsters. Instead of having to write out a page of back story for orcs in my campaign world, I can just say "Usually Chaotic Evil." This is very important for new and young players, because it helps introduce them to roleplaying without requiring a high level of intellectual sophistication or effort. It's also helpful for players who enjoy "break down the door" campaigns that focus on combat without throwing away everything related to roleplaying.

It allows you to just look orcs and say "oh, orcs are usually Evil" and kill them. And not "hey, these orcs are people too. Perhaps I shouldn't be killing them. I should investigate their culture to find out more about what truly drives them and whether or not my violent actions are justified. And now that I think about it, it's rarely moral to kill anyone unless they're directly threatening me, my family, or my way of life. Perhaps I should return to my home town and invest more in the Profession Skill."

If you don't like that style of play, that's ok. The game is flexible enough that you can easily change the alinement rules, ignore the alignment rules, or add long back stories to anything, without sacrificing or changing 99% of the other rules. But the default rules should be easily understood and usable, not a long moralizing digressions.