Yea, I think that is is not about if Ume is innocents or not, it was more about fear factor, as well as her destructive power. Most people around her currently is scare of her because she is a shapeshifting giant serpent monster, not because she killed or destroyed the city, but the fact that she did, and could just do it again.
Gargan.....um.....he would said "We share a drink, so I refused to believe that she is a mindless monster, or even a monster at all....Danger she might be, but she is not a beast that needed to be chained up."
Interesting question that I just thought of..... If your character is a video game mob/boss, what kind of items would ya drop???
Mine would be something like 'An Explorer's Notebook', 'Aarakocra's Feather', 'Marked Map (Unexplored)', and a 'random piece of unrefined gemstone or seedlings from Gargan's collection'