Goose chase meme. In the first frame, the goose asks "all the data is encrypted?" In the second, the goose chases a person, asking "encrypted how and with whose keys, motherfucker?"
Correct according to whom? The word has a long history of being used with a singular verb. The dictionary indicates it is usually used with a singular verb. Only a small number of people insist on trying to override this.
Who cares if it is plural in Latin? Once something moves into a new language, it’s not beholden to the old language. We don’t use a plural verb with “spaghetti”. Germans borrowed the word “party” from English and they pluralize it as “partys” — they don’t need to follow our rules for what is now also their word.
Don’t give in to these people who claim that “data” is supposed to be plural. They are treating a personal preference as a fact.
To be fair, German (and other languages) borrowing from Italian is a whole can of worms, but you're right: Borrowed words don't need to follow all the declination or conjugation roles from their original language.