Ah, this old debate again.
I've posted my views on this too many times to get into the details of it again, so I'll just say this.
Superman has killed people in almost every incarnation across formats, decades, and continuities. It's not a common event, but it's relatively consistent.
To say that Clark wont ever take a life is to ignore a consistent character trait we've seen over and over. People might ignore it, downplay it, or wave it off as bad writing, but it happens. We don't have to like this aspect of Clark or his history, but if the goal is to keep Clark "in character" then yes, he's willing to kill. He hates doing it, it usually weighs heavily on him, but it's there, from the Golden Age to the modern Age, and pretending it isn't is putting blinders on to maintain an ideal that Superman himself has never really tried to live up to.
This debate is just an aspect of the legend being bigger than the man (character) that has plagued Superman since before any of us here were born.