Was it the republicans that hired him to be a mercenary and tattooed a totenkopf on his chest? Well, i guess it probably was, but I kinda think they don't want us to think about that too hard.
Using Fetterman as a cautionary tail to make people think a little harder about who they support is not making other candidates answer for what he did. It is called "learning" and its a thing we probably should be doing more of.