Good points. During her powerless mohawk days she had no reservations about killing. To add another example, she knifed Callisto in the chest and left her for dead. Back in those days, Cyclops was the champion of "the ends NEVER justify the means, and X-Men don't kill!" Storm, on the other hand, had the opinion that you have to move with the times and kill if necessary. Now they've both done a bit of a reversal. Maybe Storms moral compass is "the opposite of Scott."
Didn't she also kill Marrow by ripping out her heart?
(Who survived thanks to having two hearts...