Since David F. Sandberg pointed out the Easter egg himself, he probably hoped some fans would put the pieces together, even if it took multiple viewings. The director has been sharing little Easter eggs for the past year, long before the movie even opened — including nods to Man of Steel, and a copy of The Daily Planet in Freddy’s room, with a report on Lex Luthor.
Article source: https://www.cinemablend.com/news/2470305/shazam-director-points-out-a-joker-easter-egg-some-fans-missed