From a wikipedia article:[1]
During his career, Mercury's flamboyant stage performances sometimes
led journalists to allude to his sexuality. Dave Dickson, reviewing
Queen's performance at Wembley Arena in 1984 for Kerrang!, noted
Mercury's "camp" addresses to the audience and even described him
as a "posing, pouting, posturing tart."
I think it may not refer to "camp" as a place (or encampment), but to a gay-related slang that means "a man who behaves in an ostentatiously effeminate way" according to the Google Translator.
Best Answer
Stoney B's definition is right; however, camp is by no means exclusive to the gay community. In its non-gay applications, it's sort of a 1960s word. In today's English you might say "over the top".