To be fair, there are settings to disable the automatic downloads of media (primarily used for WiFi vs. Cellular automatic download, but can be disabled completely).

And it's part of them trying to get a better user experience so that when you open/scroll through the app, everything's already loaded.

Obviously, there's a detriment and a double-edged sword: either the app sucks because it takes long to load your feed or the app sucks because it drains your battery