If you insist they give up their culture immediately you will be seen as trying to take away their culture. Just like how gun rights advocates perceive attacks on gun culture.
Solidarity is a normal reaction to real or perceived hostility. In history the social pressure to assimilate resulted in immigrant collectivism in order to support each other; Chinatowns, little Italy and a myriad other ethnic enclaves formed partly because of this pressure.
I don't think there should be any codification of what behavior should be tolerated. Refugees and immigrants entered by legitimate process, they should have the same rights as everyone else: to do whatever they like that's not illegal, believe however they like and even to campaign for change. Equal rights, especially by the law. Anything else creates a secondary class of people with fewer rights.
(Leaving aside that courts have defended human rights of non citizen visitors and illegals.)