peppy said:
He refers to himself as a "nationalist" and proudly described Breitbart as "we're the platform for the alt-right". So he doesn't explicitly write it but hires the staff (Milo, for example), sets the direction and provides the megaphone through which they can espouse their racist, xenophobic, sexist, anti-semitic rants.
Anybody that believes America's needs should come first is a nationalist. The opposite would be a globalist, which is what the Bush's and Clinton's have worked for their entire careers (open borders, free trade, and pro war). Being alt-right means you reject the globalist aspect of the Republican platform. That's it.
Another aspect though is the complete rejection of political correctness, and the way Breitbart has chosen to express this is by writing sensational and offensive headlines as a means of reclaiming their 1st amendment rights in the press. This is where I differ with them, since I believe in more civil discourse, and I wouldn't call my self alt-right for this reason.. but a nationalist, yes. I believe taking care of America's needs comes before taking care of the needs of other countries.
The reason I voted for Trump was because we shouldn't be intervening in civil wars across the world (Libya, Syria), nor should we be toppling dictators willy nilly (Iraq) unless there is a legitimate threat to our national defense.