Nice deer and nice rifle.
Nothing wrong, in my opinion, with using a firearm, so long as it's done in a responsible way. It's the hunter who is responsible, ethical, moral, aware, etc. Not his or her equipment. We tend to prefer bows, but I for one do not condem a guy just for his equipment use. I do the vast majority of my hunting with a bow, but - like you said - sometimes it's good to get meat in the freezer quickly. I may take a rilfe out later this year to fill a last tag. No shame in that.