Wikipedia says the first usage of the term "alternative right" was by Paul Gottfried in 2008 (http://forward.com/news/national/348372/meet-the-jewish-pale...)
It also says that the first usage of the contracted form "alt-right" was by Richard Spencer. https://www.adl.org/education/resources/backgrounders/alt-ri... http://www.newyorker.com/news/benjamin-wallace-wells/is-the-... and https://www.nytimes.com/2016/11/21/us/alt-right-salutes-dona... quote Spencer as claiming to be the person who coined the term. And there's like a dozen other citations on https://en.wikipedia.org/wiki/Alt-right
Where are your sources?