Personally, i'd take her accounts with a grain of salt. I don't find her to be a credible witness, nor have I seen evidence of those two being "best friends". I know Rose has said this but I question it. IMO GP did not make the same claims through her posts.
When DV isn't packaged in black eyes and physical altercations it can be hard for others to recognize (like BL antagonizing and emotionally abusing GP). I am in no way excusing GP for hitting BL. I think this relationship was volatile, toxic and unhealthy for both of them, obviously it ended in murder.
I think BL was/is a master manipulator and was harmful to GP in myriad ways. Personally, when someone is an abuser I believe they work hard to hide it from the world. When they (the victims) are exasperated and grasping, they do whatever they can for attention or the anything to "make it stop". IMO BL is the former and GP is the latter.
Again, JMO and based on the small snippets we've all seen.