I am being mistreated and am trying not to engage. I would send mail saying:
Just to keep you informed, K and I decided, for Fall, to:a/ let situation A unfold as it will.b/ support B if they want to work toward C.
c/ support B if they want to work toward D.
I wanted us also to create E, but I don’t think we will. I regret that, but I hope we can make it a regular event starting next year.*
About R, it is you who misunderstand. I have thought very carefully about all you have said. I also have a great deal of experience and expertise of my own here, and my conclusions are in line with those of other experts.
*Update! We are creating E!