True- the problem is, that not all killings, even of the Innocent, are explicitly Evil Acts.
Murder is specified as an Evil Act in BoVD (and FC2) but it's not defined in D&D- at least, not in terms of Killing the Innocent.
Thus- if killing the Innocent would be Murder (or Reckless Endangerment of Life, as mentioned in the second BoVD example) then it can qualify as an Evil Act.
But if it's not murder, then we end up in greyer territory.