I'm a bit skeptical with the title talking about evidence of cannibalism. I believe the subtitle is more accurate, because the evidence point to:
traces of manipulation of human remains
Cannibalism is the theory of this article, not the evidence. The evidence are:
individuals were dissected immediately after death. Cut marks on skull fragments indicate that the muscle attachments and scalp were removed before the long bones were smashed to get to the bone marrow.
The question what for is a legit one, but the answers are just theories.
Just to be clear, I don't deny cannibalism is a thing. Some of us grew up learning in kindergarden the lyrics of the popular cannibalistic children's song Il était un petit navire / War einst ein kleines Segelschiffchen / Itan ena mikro karavi (wiki)