Errrrrrrr, people are losing sight here.
It's not a protest against the manager. (though he's clearly throwing diesel in an already burning fire) It's a protest about accountability and communication. How are the club planning the be competative again. Lay it out, warts and all.
I have said before, a walk out doesn't work unless it's substantial numbers, 10k+, it's not going to happen. If the team is playing 'ok' then most will carry on watching. Just throw tennis balls on the pitch. It's visual and it actually stops play. Even better, do it just before KO for the next telivised game. People tuning in from all around the world and wondering what on earth is going on as stewards and ball boys spend 5 min clearing up so we can get started.
People are not paying between 30/50 quid to walk out. A cheap tennis ball is a quid. Easy.