We should account for deaths from pollution, but if we are going to do that, we should be willing to do that for 99% of aviation fuel that has nothing to do with reserves & safety margins, in addition to fuel used to drive cars.

Any regulation short of "carry infinite fuel" will be a trade-off, and entail some risk and anyone involved in setting these knows that. Zero may not be our actual target or even possible, but it is a useful aspiration to ensure that everyone is pulling in the right direction.