Five years ago Laura Loomer, a far-right activist with a history of expressing bigoted views and a knack for generating publicity, filed an application for a trademark to protect her work in “the field of political activism.” Ms. Loomer, 31, part of a generation of web-savvy right-wing influencers, decided to trademark the term she had coined for her signature move of ambushing people with unexpected, often embarrassing questions. She called it getting “Loomered.” Already a well-known...