I can't look closely at your quote in context because you don't provide a link to it.  Even so, a rate of victimization doesn't say anything about who the perpetrators are, just who the victims are.  It may just mean that more lesbians have been assaulted by family members.  The point is you can't tell from the statistic you've posted.

And it's another red herring being raised in this debate -- when the question posed was about sexual assault in same-sex relationships, your "statistics" on domestic violence doesn't answer it.  They are different things.