The core beliefs of the alt right are correct. Any nation has to put the interests of its people before others to survive. An endless flow of migrants will inevitably destroy the individual rights that liberals think they are defending. Right now we have no way of integrating racial groups without violence, living separately is the only peaceful outcome.
In my opinion and experience, people who hold extreme views are unable to listen to facts, or at least resent facts that do not support their views. This is true with extremists of all forms, from the alt-right to the extreme left, libertarian, authoritarian, anarchist, capitalist, jihadist, etc.