Because they are often the perpetrators. Indigenous peoples have a high incidence of drug abuse especially alcoholism. This is well documented as to not having evolved with alcohol. A lot of indigenous people's live on reservations and they are poor (I have seen some of these places). A lot of money from the casinos go toward rehabilitation programs. So the addictions + poverty often = abuse.

@JackPedigo
I think domestic abuse and ecocide both perpetrate violence toward indigenous women. I knew a young woman who went through terrifying gang rape. I tend to think indigenous men are violent toward their partners, not to other women. I wonder if that is correct.

@AnonySchmoose Depends on ones definition of 'partner.' I was friends with a woman (non-indigenous) who went with a Native American. She said he often went fishing just to get drunk. One time it went too far and she had to call the cops. It ended up with jail time and a permanent restraining order. She gave me his old Coleman stove and I cleaned it up and still use it. I am reminded of the original owner every time I use it. Of course there are non-natives with natives and visa versa.
Speaking of which I just watched a wonderful and true story on Netflix titled "Te Ata." [imdb.com]

@JackPedigo
Te Ata's dancing/storytelling was unique. I loved how she was honored with invitations to perform for the FDR & Eleanor, King George VI & Queen Elizabeth, and in many other nations. That she included stories from other Native American tribes helped preserve their cultures as well as hers.