You bring up some good points, however Barry used the word "we" if I remember correctly, not referring just to himself. Team Flash in general was responsible for the deaths of their enemies. It is true that Eddie never communicated killing Thawne, as it was a split-second decision, and Devoe's wife was not part of Team Flash, but Caitlin and Iris certainly were part of Team Flash. I don't think the plan was ever to kill them, but they always did. For instance, with Devoe, the plan was to bring good Devoe back and simply convert him to their side, but when they saw that good Devoe was dead, the plan shifted to bringing Ralph back to kill Devoe.
All in all, good points, but I think they did kill all their major season-long villains. They did not plan to kill their enemies, but the battle always forced them to do so. Barry said, "There's always another way," but they always needed to kill to save the day.
