Users have better things to do than constantly click "report spam" buttons on minor variants of the same content a million times in a row. People see spam reporting as equivalent to filing a complaint i.e. the company failed and they're informing it that it needs to do better.

Automation detection and privacy are orthogonal. The ideal bot detector yields a single bit of information: bot or not. It doesn't need to try to de-anonymize users or anything like that. As for UX, well, spam is a bad UX.

There are a million creative ways to solve this that don’t involve dark patterns, poor ux and wasted resources. This comment does a better job than I’ve done explaining:

https://news.ycombinator.com/item?id=27664604

That comment doesn't explain anything. It just says: spam? Remove the incentive.

The incentive is money. You can't just wave a magic wand and get rid of the incentive to spam things. Asserting that you can is wishful thinking.

Bots will then generate millions of fake users, upvote their own content and downvote all other competing content.

You realize there’s no captchas or fingerprinting on this site right?

This is an absolutely tiny site.

Things that work for small sites fall apart once you get 10~100 million+ people.

Look, I help do the actual user moderation for a large (10m+) subreddit, and it is a god damn nightmare. Plus, on top of that, we have to do automated bot detection anyways, because otherwise it's just neverending bot spam.

I worked on a site with 200M active monthly users. No captchas. It’s totally doable.

Reddit is actually a good example of having millions of users with no captcha. They “fixed” their problem with user moderation.

You chose to become a moderator, so it must not be that much of a nightmare.

EDIT: Reddit does have a captcha now. My guess is it came along with the other users hostile changes in the new design.

Reddit does require a captcha and has for a long time.

edit: They have for at least the last 6 years based on online questions. Long before the new design.

I see you are correct. They did not used to though.

Reddit repost bots execute with full (though unintended) support of moderators and legitimate users.

Users definitely don’t want to be exposed to spam much less have to take action against it.