No matter if we only trap soul from the enemy who want to kill us, but the practice of stealing their soul for our gain is totally not compelling and disrespectful. Not to mention that i never see any enemies who cast Soul Trap on us or using Soul Trap enchanted weapon against us, i mean if our character die, never shown got Soul Trapped even by the most evil enemy in the game.
In Oblivion, at least we hear some complaint regarding Soul Trap practice, it is from a Red Guard mage in Cheydinhal, Trayvond...he says
"....I still have strong prejudices against necromancy, summoning, and illusion. Profaning the remains or souls of the dead is just wrong. And I'm uneasy about tampering with other's minds and trafficking with Daedra."
But in Skyrim i am yet to see some arguments about Enchanting and soul Trap practice by anyone...
It just...like there is no alternative for enchantment other than involve in Soul Trap...in Dragon Age, enchantment is by using Lyrium, a mineral of magic, "magic in it's raw form" as according to the lore. This mineral that bind runes to items making the items magical. If there is alternative like that in TES world, it is pleasing....it remove the guilt for making enchantment, using and wearing enchanted item....
Think...we wear robes/armor that have someone soul bind into it....
Oh yes, doesn't the Dwenmer robots actually become "alive" because of Soul Gem in them? Isn't that Necromancy and not science?