Well - I'm not blaming the user, but that's how it's on any federated service. People don't seem to have the same complaints about email or matrix. While it's possible to create a global index of all Mastodon users, I personally feel that it is best enjoyed without it.
I have a very satisfying personal feed on Mastodon. There are personal acquaintances whose address I received directly from them - like how email addresses are exchanged traditionally. Some addresses were collected from webpages I'm interested in. All the rest are people whose comments were boosted by others and caught my eye.
All the above, together with whatever algorithm Mastodon uses seem to give me a much more interesting and less addictive experience than the traditional social media. Mastodon doesn't hand hold you in creating a feed. It does need a bit of effort. However, the result is high quality.