Color black is associated with fear. Our culture is filled with mythogocial stories where monsters are dark. Anything black is undesired in nepalese culture. So I guess this is one of the main reasons why Nepalese hate black people. The other being, "stockholm syndrome". They work like slaves to the white majority that they end up adorning the same masters. As a result the enemy of their racist masters become their own enemy.
Facebook might have worked in gas stations and faced robberies by blacks. But he needs to look beyond these trivial incidents.He needs to look at the reasons, the culture, the pattern. In other words, he need to grow up or smart up.