When Al Sharpton demonstrated in front of a Jewish business in the Bronx riling up the black masses about “white interlopers” and Jewish “diamond merchants”, he was charged with no crime. And that was despite the fact that his demagogery resulted with his mobs burning down that Jewish store and killing a person inside! The arsonist was arrested and charged while Sharpton was protected by free speech. This in no way justifies Sharpton ym’s, but does clearly demonstrate the legal rights of protesting and speech as recognized by the courts and the law.
The right to protest is a basic staple of any democracy. Even Putin in Russia recognizes this, as much as he doesn’t like the fact. And, yes, the fact that police have been at the site of daily protests in Beit Shemesh every day for months without arresting anyone for simply being there and calling the mothers prutzas, very much demonstrates its legality. The chilonim need little excuse to arrest chareidim, given even the slightest chance. Their police wouldn’t stand there every day witnessing something illegal for months and months and not arrest. They would love nothing more than to arrest chareidim if they could.