Noon
Ace of Blades
Since the majority today believes murder to be evil, it is morally abhorrent, and you would be free to doubt such a thing as it being legal would exist.
But on the same note, abortion used to be considered abhorrently evil. Nowadays, the majority, or at least the loud minority, believes it's at least tolerable, and so it's considered morally acceptable. So it does happen.
Yeah. And this can be applied to everything. Culture is a big part of what's generally deemed 'good' or 'bad' - that is, if you agree with law.
What happens when humans make contact with an alien race? For all we know, any intelligent race similar enough to our own could be active cannibals, murderers, rapists or similar - and to them, that would be fine. We might even be disgusting to them for using anti-septic wipes to sterilise our eating spaces, because that counts as harming living creatures.