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.
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.