It's too vaginacentric apparently 
In case the thread hasn't been deleted by the time you see this, it's here
'Ooffii Hardwick
1 hr ·
Message from the organisers: Our intention is to make this march intersectional and inclusive for all. For that reason we respectfully request that people ensure that their signs and apparel reflect that. We ask that you do not wear pussy hats or carry "pussy power" placards. The vagina centric theme of the Womens' Marches was offensive and entirely exclusive of our trans sisters. Genitalia does not equal gender. Whilst we understand people's desire to fight back and react to Donald Trump's horrendous misogyny, we believe the best way to do this is to fight together and for each other in a space where no one feels unwelcome, and where those spaces do not exist for us to be the ones to forge them.'
There are some very pissed off feminists in Brighton now, judging by the thread.
It's meant to be a demo in support of Muslims against Trump's racist immigration policies so I am not sure why anyone would be carrying a vagina placard anyway, but not being allowed to wear the hats seems a bit extreme.