...from the perspective of anyone who rejects the notion that god might not think or act just as they themselves do.

So looking at it as a thought experiment, if you not only accepted that god's will could include the killing of abortion providers but you also sincerely believed you'd been lead by the holy spirit to the understanding that it was god's will that you yourself in fact kill a specific abortion provider, is there any possible justification for the failure to act in accord with that will?