An actual numerical minority constitutes a “vast majority” if it serves your needs and you don’t care about (A) objective truth and (B) what people think of you. A person of sufficient sociopathy would be able to create the alternate reality necessary to make such a contrafactual statement true (at least, in their own head and in the minds of their true believers).
A person of slightly less sociopathic mindset can get around “A” by (silently) provisoing the statement “a vast majority of everyone who matters”.