I am questioning the presupposition that one chooses to make any account at all.

Using your analogy:

I don't need to create an account to view a subreddit or reddit. I don't need to create an account to view federated instances.

When I publish content on any social network I am always thinking about who it is intended for. I don't post the same things on Facebook that I would on Instagram, for example.

Users have to make the same choice of what to publish with any other social media service.

Yeah but I am more thinking about not hosting your Instance angle.

Mostly topic based federation is what I am against. (When bundled with identity)

You might be mixing up threads here, I didn't mention single user instances in my reply.