Why do people say nationalism is a bad thing?

Why's it make sense for a certain group of people to be entitled to special priviledges in a big ol' piece of land simply because they were born within its confines? I kinda think the idea of nations is ridiculous in itself, even if it's necessary to maintaining the status quo.

Basically, the "normal" sort of nationalism is widely accepted and non-controvercial, so when someone proclaims to be a Nationaist, everyone ascribes the more intense version. We're all already nationalists after all, the right and the left - the people who want to abolish borders, etc are a tiny fringe.

Its just the media that portrays it so.. like you are appreciated only if you help someone on the streets or in distress, but not when you help yourself or your kith and kin, to stay afloat.

I only go by the Airline oxygen mask. First wear it yourself, and then attend to others.

Nationalism has nothing to do with caring about the people.