Is it illegal to go to court for redress?

Of course, it is illegal, because the court ruled that it is not the right way to play banners unfairly. The correct way is to appeal or appeal. Banners can only make things big, but not solve the problem. The solution to the problem is to solve the problem through legal channels. And you will be detained or fined if you hang a banner and tighten the provisions of the law on public security punishment.

Legal basis:

Article 3 of the Civil Procedure Law of People's Republic of China (PRC) The provisions of this Law shall apply to the people's courts in accepting civil lawsuits brought by citizens, legal persons, other organizations and their property relations and personal relations.