> Being able to connect with people from around the world and share content is not a big waste to society.

That's correct. However, the ability to "connect with people from around the world and share content" is, as your parent post notes, is Facebook's "core" functionality. What does Facebook have to show for the engineers they've hired this year, engineers they've hired last year? Are read receipts on Facebook chat more beneficial to "society" than other endeavors the engineers could be working on instead?