

Well, you’re really just throwing out what-ifs. But you happened to chance on one theory that some researchers think could partially explain the discrepancy:
Being bi or lesbian still comes together with a special type of discrimination that a straight woman most likely will never experience;
Being oppressed causes stress, stress causes lack of control. The idea is it’s a similar driver to why poorer couples have higher rates of abuse.
That’s probably not the SOLE cause, but it’s likely a factor.
The numbers are pretty much a consensus among researchers. If you disagree, then the burden is on YOU to do a deep, critical analysis. I’m just reporting the conclusions of others, not doing any critical analysis. If those conclusions make you feel uncomfortable, maybe you should explore that feeling more. Although if you want to do a critical analysis, I’d welcome it.