If, when the evidence is in, this turns out to be a case of a loyal American soldier “losing it” due to the stress and horrors of war, this lone killer will be held up as an example of how such things are a terrible risk in the US military and that it’s a huge issue that needs to be addressed as many, many more could do the same thing at any moment.
If, on the other hand, this turns out to be a jihadist who put his faith before his country (as seems likely from what I’ve seen so far), he’ll be dismissed as lone wacko. One in a million. Move on. Nothing to see.
The truth is probably somewhere in between somewhere.