I don't think it's related to the (rise of the) Alt Right.

The 1980s is big in media because Generation X is starting to become the mature establishment in media. You'll note though that media is, for the most part, not alt-right - if it were you wouldn't be getting the reaction to it from the alt-right, from Wonder Woman to The Last Jedi.

The Alt Right is something else, but the main leaders seem to either be apparently charismatic youngish people like Shapiro or Yiannopoulos, or reactionary boomers like Trump and your Uncle on Facebook.

(I'm not implying Shapiro et al represent their generations at all, the same generation is giving us plenty of leaders who are bringing positive changes, from Sarkeesian to AOC, I'm just saying it's not really the same movement causing Hollywood/TV to pine for the 1980s as it is that's marching in Charlotteville, as can be shown by the fact the age group doesn't overlap much.)