There is a single rule to see tell the true motivation of a protest: is the biggest protest sign written in English (if the general public in the area/country not native English speakers)? If yes, it's probably a show to leverage CNN/BBC. Otherwise, why would protestors use a language unable to deliver messages to their own people?
Judging from your analysis, you couldn't tell the true motivation of a protest if it bit you on the arse.
Protests are shows. That's why they call them demonstrations.
And given signs are for informing people outside the protest, it is no surprise that folk will write an English one if they know there will be an English speaking news crew around.
so according to your opinion, a protester bits your arse and it's a show?
I'm a programmer and I have proposed a straight forward rule to help me understand the situation. If you have a better way, show me. If what you are saying is any protest should be supported unconditionally, and any means to attract media attention is legit, then go to Iraq and join ISIS' protest.
According to this pic: http://www.popo8.com/host/data/201409/28/3/f864d6c.jpg, this Occupy Central is a show.