A position doesn't become "relativism" just because you don't want to hear it. It's not relativism to point out that people have responsibility for their actions, nor to point out that mental illnesses do not generally make people homicidal.
Regardless of what is ultimately found out about the case, people were claiming mental illness before they had information to support that, as they do in nearly all of these cases.
Regardless of what is ultimately found out about the case, people were claiming mental illness before they had information to support that, as they do in nearly all of these cases.