Demos represent only the people who are against the government. - It is an obvious point, yet forgotten in media coverage of even miniature demos of a few hundred people. People who are happy enough with what the government is doing simply will not demonstrate. Even if the vast majority supports the government, all public demos will be against the government. The media will cover a few hundred people having a demo. It doesn't cover the vast number of people who didn't demo.
Even huge demos may not represent public opinion. Votes represent public opinion. Demos don't.
Demos represent only the people who have time to go on a demo. - Demos are dominated by young, unmarried people like students. People who have tons of time and energy and are mobile.
People who have serious jobs, mortgages, babies and children to care for, perhaps elderly parents to care for, and so on - not to mention having tired, middle-aged bodies exhausted by their reponsibilities - will not be found on demos, or travelling round the country living in tents and engaging in "direct action". They have opinions just as strong as the carefree, childless students, but they will not express them at demos. They express them at the ballot box. Governments know this, and that is why they do not take demos seriously.
Posters and graffiti don't represent public opinion either. - In every city centre in the west, one sees posters and graffiti representing various points of view. Or rather, all the same point of view, I should say.
"END THE OCCUPATION OF PALESTINE. PUBLIC MEETING ..." say the posters. Why does one never see posters saying: "STOP SUICIDE BOMBINGS. PUBLIC MEETING ..."? It is not because nobody subscribes to that view. It is because only certain types of people go round putting up posters and having public meetings. Posters do not represent public opinion, and should not be taken seriously.
Similarly, "NO WAR" and "DON'T ATTACK IRAQ" reads the graffiti. Why does one never see graffiti saying: "BRING DEMOCRACY TO THE MIDDLE EAST" or "END ISLAMIC LAW"? Again, it is because only certain types of people spray graffiti. Graffiti does not represent public opinion, and should not be taken seriously.