This is just all so ridiculously disingenuous though.
Regardless of who has lied to whom about what, and who thinks they know the truth about what, there were two FB groups - many of the people who were in one have now left. There are now a lot of people from the other FB group, including the OP, asking why they all left on this thread.
It is just silly.
What are you doing it for?
What is the point in going through any of this again?
The whole thread seems like goading to me.
If you have concerns about where a particular poster is, for example Sakura, who left maybe a year before the board reorganisation so presumably did not leave while Portofino was on holiday, why don't you just contact her and ask her?
I do not see the point in blaming it on MRAs or whoever - if you want to know why a particular poster left, contact them and ask them. Ultimately MN is just a board, and people find other things to do. I don't know anybody who feels they've been silenced - they're just busy elsewhere.