If the gathering is large enough they can't stop it and will back down. See the yellow vests movement.
That only works for gatherings not associated with a legal entity.
For example a sports club ( football? ) can't ignore the rules or it will be fined / closed.
It depends. In France unoins will organize public gatherings and won't be fined or closed because they have real power to shut down a whole sector of the economy and the ability to negotiate with the government.
In some counties it is much broader than that. Painting it as hyperbole sounds hollow if you are downplaying it yourself.