Why in China during anti-extradition protests do the all the congregate hold up the very same red No Extradition signs?

Imagine if they did not.  Imagine if everyone had a different sign.   Do you think anyone could read them?  

This way everyone is saying they are all in agreement.  They all hate the same thing.  


It would be like everyone in America ripping out a different page of the Mueller Report and putting it on a sign and marching.  It would not make the same effect as IMPEACH and IMPRISON TRUMP.