Does it harm any one? No
Does it benefit anyone? Yes
Whom? BJP, Shiv Sena
How? Read further
Shiv Sena: The organization that existed on the basis of regionalism was loosing its base to MNS. MNS was snatching its vote base in a rapid speed and in-spite of all its efforts, Shiv Sena and its Chief Bal Thakare were only watching MNS growing but weren't able to stop MNS.
They needed something that could revert the Marathi Manoos issue back to Shiv Sena, and for that, they needed someone like RSS and BJP to oppose this hate politics. As soon as RSS officials issues statements, Shiv Sena did not spend a minute in garbing the issue and opposing it, they did not give a chance to Raj Thakare to jump in. As it stands today, it sounds like Shiv Sena is the lone party standing for Marathi Manoos.
BJP: RSS and BJP did not oppose Shiv Sena or MNS on this regional hate politics ever, though Shiv Sena has been doing this politics from 1960s. But right now, when BJP has lost its grounds, and they badly need a win to boost their morals and Bihar elections are approaching, looking at the number of migrants from Bihar in Mumbai, what could be the better time for this drama? That is why RSS issues such statements and BJP jumped into it and said that they do not agree to the Shiv Sena ideology of regionalism to gain political mileage in Bihar.
I would not be surprised if Shiv Sena and BJP split for now as there are not elections approaching in Maharashtra thus that would not negatively impact either of them, but positively impact BJP in Bihar. However there will be a reunion after Bihar election and before any major elections in Maharashtra for sure. Because this is pure Noora Kushti.