Who is "defending" Sarah? No one has said anything like that. It appears that your formulation is that we either accept that she is a Satan-worshipping drug addict, or we are "defending" her murdering someone. To the extent you believe that, you should avoid referring to others as crackpots.
It appears that she has murdered someone in cold blood, and dismembered the corpse. We do not need to heap extra evil on her at this point in order to explain the deed. The evil embodied in her acts is quite enough.
"We do not need to heap extra evil on her at this point in order to explain the deed. The evil embodied in her acts is quite enough."
I never did such regarding Sarah but by your definition,
"heaping extra evil on a person", it's done every day by many many people regarding people in the news discussed in this or any forum on the internet or any where else.