(But she doesn’t point at anyone else. not even Mark who she also gets furious with. In a scene with him she just points to herself in fact..)
So, her pointing to Ruth underlines how she’s able to express herself physically around Ruth since she takes up more space with her body when she points. I don’t think she feels comfortable taking up more physical space around Mark, even at her angriest, which is one reason she never points at him in her scenes with him. Which is one reason Mark takes one look at her in 1x07 when she looks like she’s on top of the world and she crumbles and leaves the ring in shame. Which is one reason that, even after giving a speech about how wrestling makes her feel like a super hero in 1x09, she still leaves wrestling to try and work things out with Mark in 1x10. Because of course she does. She shrinks around Mark.
She allows herself to take up more physical space around Ruth in a lot of ways and to express her weird, bodily impulses….like pointing 24/7.
I think the finger pointing is yet another thing that is randomly really complicated? Like the gesture suggests casting blame (why does she cast blame on Ruth but not Mark then if she doesn’t use the gesture against him…again I think it has to do with feeling comfortable expressing herself around Ruth and that she truly blames Ruth more because she cares more for Ruth than she ever did for Mark, so Mark’s betrayal hurt less and she was able to let go of Mark while she continues to reach out in this fucked up way (physically and emotionally) to Ruth.). She also uses the gesture to choose Ruth, to choose to wrestle with her in 1x06 and 1x10. Just like her destructive anger against Ruth becomes used for good with the wrestling, so too the pointing. And, then there’s the question whether this gesture suggests she’s reaching out to Ruth with this gesture since she’s lessening whatever physical gap there is with it…I don’t know.
In conclusion, Debbie, get it together.
