I'm the last person to be cheering for a multinational conglomerate, but...

The global food giant argues that Hampton Creek’s Just Mayo is not, as Unilever lawyers wrote, “exactly, precisely, only and simply mayonnaise,” as defined by the dictionary and the Food and Drug Administration, which says mayo must include “egg yolk-containing ingredients.”

... Unilever's kind of in the right here. The FDA says what mayo must contain. Dudes call it mayo when it doesn't contain it. While they're sort of stomping all over the FDA's territory, they're pretty much correct.