I agree that crosswords often include cultural references that lean towards certain demographics / assuming particular education, and that can feel exclusionary if you don’t share that background - and there's even an argument to suggest snobbery might be behind those choices.

But I disagree that that makes it for snobs. Snobbery is more about an attitude of looking down on others or their tastes, whereas knowing Latin or being a fan of opera is really just about exposure.

Sure, there exist some (too many) opera fans who would say something like "it's real art compared to pop or hip hop being low class trash", but that's not a defining part of liking opera and plenty of people who like opera aren't snobs. Ironically it's a different form of snobbery (sometimes called reverse snobbery though personally I hate that term), to dismiss anyone who learned Latin or who likes opera as being a snob!