To put it another way: Google search works by making their own copy of the Internet. It's much smaller scale, but similarly, atproto makes downloading the entire social network relatively easy. Many ordinary techies have the resources to replicate the whole thing if they wanted to. To query your replica, you use a database, designed however you like.

So the question is, are you okay with giving random people a mirror of your public posts? After all, they're public. It's like putting them in a repo on Github for anyone to clone.

Google's Go Module Mirror is a similar but more specialized service that has a copy of all the Go modules that anyone has published on the Internet.