Most don't say outright that they want zero risk. However, when you start questioning why they want something removed from the market, or restricted for use it becomes "because it's potentially harmful." When you ask for proof, actual proof, that it's harmful then you get "it's been shown in these other contexts to be harmful and that's good enough." Say, well, this is a different context, and we don't know at what levels or even really IF it actually IS harmful, then you get "well the potential is good enough."
That is an (incomplete)argument for zero risk.
What would you like to see that would Justify removing a Chemical Flavoring from an e-liquid?