It seems to me that JR is pushing for the defense to be along the lines of 'Sandie was racist, and homophobic and transphobic, she was such an awful person filled with hate that she set out on purpose to provoke the conflict with Dr Upton. Because she's so hateful. Did we mention hateful?' I also got the impression JR is implying that SP came up with the menstrual flooding as a way to further provoke the situation, or to make her own standing better in the scenario, ie that SP wasn't actually flooding, she was looking for ways to make the conflict with DR U go more her way.
It's worth noting that this is JR's job, to muddy the waters, make the whole thing less clear cut, to use all available info to give her clients the best defense, and if she had this info and didn't use it, then she wouldn't be doing her job well.
I strongly suspect though that if you go back through those messages on that chat, SP will not have been the only one sharing messages of that tone. I totally oppose racism, and I don't like at all that those messages have been sent by SP, but I do believe she will likely have been sending them in the context of what she believed was a welcoming audience. No one randomly appears spouting racist nonsense on a group chat if they're not sure of their audience. And if they did, and it wasn't welcomed, most normal people would say something, or block, or boot them from the chat, not carry on engaging with them and going on bloody holiday with them.
I'm very interested to see what NC makes of this witness.