Top 10 Reasons Why StrangerVille is the Worst GP yet [SPOILERS]

I think a choice was made. You can't make something stop to be vaccinated that doesn't want to be and that happens later. I don't think syringes would help then so they just took this approach to prepare the player in a sense for something that happens later.
Also about the splash thing.. it can be good for stories as you play .. if the possessed are more of a zombie like creature it give us more options to work with.. not less.
Especially if you use it for more than just the aspiration story line which I do and plan to do.