- Does Instagram prioritize scantily-clad photos of attractive people over scantily-clad photos of relatively less-attractive people?

- Is the prioritization based on a machine analysis of the photo, or on the response of earlier users to the photo?

- "While [the skew towards nudity] was consistent and apparent for most volunteers, a small minority were served posts that better reflected the diversity published by content creators." Are the majority people who have clicked on plenty of attractive scantily-clad photos? Are the minority people who have been presented with such and avoided clicking them?

I would bet the latter. Why go to the trouble of analysing difficult stuff about body structure, when you can just let users "decide".

I think we should formulate a law, something like "every internet imageboard, if left to user-moderation, will eventually turn into pr0n".

If my theory of "It's not Instagram that prioritizes attractive people, people prioritize attractive people" is right, then yes, less attractive people are less attractive and therefore less prioritized.