These Up/Biharis would not dare to go to Tamilnadu or Karnataka cause they know that they would not get easy access there as Maharashtra. But is politeness of Maharashtra not the very reason for endangering Marathi culture?
As a one nation people can and should go and settle anywhere and Marathi people too are migrated to many parts of the nation, but have they not assimilated with the local culture there? Are they not speaking local languages? So why should Maharashtra not expect the same from outsiders, and if these same north indians go to Tamil nadu don't they learn Tamil there? then why don't they do in Maharashtra?
Maharashtra has always been a proud growth engine for the nation. In most difficult times Marathi people were among the first to die for India. They would never mind to share their bhakari with other Indians, but why should they do it? just because UP and Bihar are at the hands of Lalu,Mulayam and Maya? And people there are ready to fight against Maharastrians for resources in Maharashtra but not for their due rights like good governance in UP/Bihar? And it is responsibility of only Marathi people to observe restraint and maintain peace?
May be you can arrest Raj and make him silent, but it will not change the reality. You must understand and address the concerns of one peaceful, lawful and progressive cultured community - Marathi manoos.