There Is No Reason For Shen To Be Neutral
I expect many downvotes (which is funny) but thing about this logically first.
Outside of several priests exterminating demons, I haven't heard of any times within the lore of humans attacking the spirit world and trying to slaughter demons or other creatures from the other dimensions. However, these creatures are constantly coming over to Runeterra and trying to cause as much mayhem as possible (void creatures, shadow isle creatures, etc.) Shen isn't as much neutral as he is extremely reactionary to violence. I read the story about some priests that were destroying some spirits and Shen decided to murder them. I took the side of the Holy men in this story because they are probably sick of Rek'sai, Kog Maw, Cho, Shadow Isle ghosts, and seemingly thousands of other creatures appearing from out of thin air and slaughtering everybody they see. They probably said "we are going to fight back and try to exterminate the ghouls from this area to save our families from more attacks."
Put yourself in the Holy man's shoes. They spend most of their day praying and living a largely uneventful life. Every so often the sky opens up and unkillable monsters blindly kill everything in sight. These demons may have slaughtered their families or loved ones and completely devastated their lives. So they finally say to themselves "let's be proactive here and try to stop some of these monsters from wiping us out by getting to them first." As soon as they do that, Shen arrives and murders them for it (another instance of Shen being late to the battle). Maybe Shen should have talked to them about why they did it and he probably would have found out that these guys are sick of waiting for Shen to hunt down monsters AFTER everybody has been killed like on the boat. They were being resourceful and proactive in ridding the spirits themselves.
And let's be real here. These demons don't have a culture or conscience. They have done nothing but act like piranhas waiting for a chunk of meat throughout the entirety of lore. I find it hard to believe that Shen will ever fight against humans again to protect demons that they are picking on, whereas he is going to spend 99.9 percent of his battles protecting humans. I don't even know why he wants to keep the two worlds balanced. The spirit world keeps going to the physical world picking fights but I can't imagine the people of Runeterra ever having incentive to want to go to the spirit world and try to mess up some of the spiritual creatures for fun or any other reason except they are sick of constant supernatural attacks.
Anyway, I enjoyed the story nonetheless and am excited to hear more about Shen. The writers are very talented in making these stories come alive. Hopefully Shen realizes his false sense of being neutral is just an interesting character flaw that he will figure out was incorrect along his journeys.
is a spirit and he is someone who protects the balance of the world,so saying that "spirits have never done anything good" is also wrong