1,700 protesters do not in any world represent the majority will of 70 million people.
You don't understand how freedom and democracy works, do you?
They don't have to. They should be free to express their dissent.
That is what all of this is about. Monarchists do not have an inalienable right to have their precious coronation free of banners expressing disagreement with having a monarchy at all, that's the whole point of living in a free and democratic society.
On your other point, try emigrating to NZ, Canada or Australia without meeting a whole raft of preconditions around your qualifications, experience, earning power - even your health. Not so easy.