I don't suppose that they really expected viewers to think less of Roger for not shooting, really, though it's possible. The pathetic thing for me was the vehement threat repeated over and over, without any thought for how ridiculous it is, when you should know you can't possibly follow through on it. It was as if for Roger, the bluster substituted for acting. I don't know if DS's makers agreed with me.
Apparently Burke's image of Roger is now of someone who would never have the nerve to kill intentionally. We're not supposed to respect murder of course, but choosing your actions carefully and wisely, and then acting on them even when difficult, and then standing behind those actions afterward and facing the consequences is, in a general sense, admirable. Roger was showing he was incapable of any of this.