Most of us were forced to read 1984 and didn't really enjoy it. ATLA however, is something that we organically grew up with through high-school / college and actually paid attention to.
My group of friends would be aware of 1984 concepts... such as "Big Brother is Watching" (phrases / concepts which have escaped the book and become a thing of their own). But I don't think we'd recognize the phrase "At War with Eurasia".
Honestly, the only reason why I remember "At War with Eurasia" is because I was a quiz-bowl player and was forced to memorize key phrases from many books I barely read. Even if I did read 1984 in my high school classes, it never actually stuck with me.