By not spitting into the wind. It's infeasible to try to prevent all web scraping from any possible IP which is what you would need to do. Reddit just took advantage of the media topic as a justification, they're not doing anything real.

Is your web site indexable by search engines?

The way that works is they make a complete copy of all the public content on the site — anything that a non-logged-in user can see — and then use that for indexing. Googlebot, BaiduSpider, Bingbot, DuckDuckBot, etc. simply copy the public data from your site onto those companies' own servers.

Once they've done that, they can do anything with that data, without further interaction with your site.

That includes using it for ML/AI training.

You cannot technologically prevent that without becoming invisible to search engine indexing. That means not being public on the web.

Your choice. You can't both be public and not public. You can't be both indexable and not indexable.

Public federation requires being public. Which thereby requires being indexable, which thereby means everything written here can be ingested into training pipelines.

That's simply true. It's not good or bad; it's just true. Your alternative is to not post your words on the public web.

I think it's inevitable. They're going to scrape every shred of data they can access. I would prefer to interact with real people tho.

With the fediverse, couldn't they just create their own private instance and let all the other instances just feed them data?

As long as they don't do anything to inspire other instances to defederate with them (which by not posting anything and not drawing attention they probably won't) they can just sit there pulling data.

iptables.