I'm Confused About The Lore Of Lost Sanctuary Dungeon

So, Studying the Corrupt quest is an interesting quest with some good lore. In the quest, it's about the story of man called: Garoth, who tries to find a cure for the corruption. The quest is fairly interesting and it set me up to thinking the dungeon would be centred around corruption. But, from my understanding: Garoth somehow found Lost Sanctuary bridge, found the species living underneath the bridge and decided a great way to spread corruption is by enslaving animals? This dungeon doesn't make too much sense to me. If anyone has a better understand then please tell me.

 

The Lost Sanctuary Dungeon is primarily known for being the weakest dungeon lore wise, as it has a lot of unanswered questions surrounding Garoth and his true intentions. You've gotten a general understanding of the dungeon and lore surrounding it, however, so do not worry about feeling like you've missed something or don't understand it.

It's just an old dungeon that gets a new coat of painting every once in a while, back when the lore wasn't as sound and bosses like this were either revamped ideas or replacements for ones that made no sense lore wise. (The old Lost Sanctuary was an Animal dungeon with a lava cow boss, and ever since the gameplay update when Garoth replaced the boss, they've been trying to fit him to the lore as best as possible whilst keeping the general idea of the dungeon.)