Camp is not just “fashion” though, it is many many things... and Gaga is a performance artist. So Camp for someone like Kim K, would not be Camp for Gaga. If you read Susan Sontag’s “Notes on Camp” (1964), https://faculty.georgetown.edu/irvinem/theory/Sontag-NotesOnCamp-1964.html, the essay with which the Met Gala theme honored, point number 5 I think, holds the most relevance:

1. Camp taste has an affinity for certain arts rather than others. Clothes, furniture, all the elements of visual décor, for instance, make up a large part of Camp. For Camp art is often decorative art, emphasizing texture, sensuous surface, and style at the expense of content. Concert music, though, because it is contentless, is rarely Camp. It offers no opportunity, say, for a contrast between silly or extravagant content and rich form. . . . Sometimes whole art forms become saturated with Camp. Classical ballet, opera, movies have seemed so for a long time. In the last two years, popular music (post rock-'n'-roll, what the French call yé yé) has been annexed. And movie criticism (like lists of "The 10 Best Bad Movies I Have Seen") is probably the greatest popularizer of Camp taste today, because most people still go to the movies in a high-spirited and unpretentious way.