My french is not that great...I think you say it is illegal to fight back because of collusion. According to Wikipedia
Collusion is an agreement between two or more parties, sometimes illegal and therefore secretive, to limit open competition by deceiving, misleading, or defrauding others of their legal rights, or to obtain an objective forbidden by law typically by defrauding or gaining an unfair advantage. It is an agreement among firms or individuals to divide a market, set prices, limit production or limit opportunities. It can involve "wage fixing, kickbacks, or misrepresenting the independence of the relationship between the colluding parties". In legal terms, all acts affected by collusion are considered void.
I really don't see how asking people to protect their investments by just making sure that their shares can not be used to borrow against would be considered collusion. There is nothing illegal to suggesting to others in the open (as in this blog) to stratagise and fight back against a group using our assets against ourselves.